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Biomedical subjects

M Berge

Publications and source records attributed to M Berge.

At least 19 recordsLinked to original sources
PubMed1998

Concentrations of cat (Fel d1), dog (Can f1) and mite (Der f1 and Der p1) allergens in the clothing and school environment of Swedish schoolchildren with and without pets at home.

To investigate whether our hypothesis that cat and dog owners bring allergens to public areas in their clothes was true or not, we studied the levels of Fel d1, Can f1, Der p1 and Der f1 in dust from the clothes and classrooms of children in a Swedish school. We also investigated the levels of allergen in different areas in the four classrooms used by the children. Thirty-one children were selected in four classes, forming three groups: cat owners, dog owners and children without a cat or dog at home. Furthermore, a group of children with asthma was included. Cat and dog allergens were detected in all 57 samples from clothes and classrooms. Mite allergen Der f1 was detected in low concentrations in 6 out of 48 and Der p1 in 5 out of 46 samples investigated. The concentrations of Can f1 were higher than those of Fel d1 in samples from clothes (geometric mean: 2676 ng/g fine dust and 444 ng/g) and classrooms (Can f1: 1092 ng/g, Fel d1: 240 ng/g). The dog owners had significantly higher concentrations of Can f1 (8434 ng/g fine dust) in their clothes than cat owners (1629 ng/g, p < 0.01), children without cat or dog (2742 ng/g, p < 0.05) and children with asthma (1518 ng/g, p < 0001). The cat owners did not have significantly higher levels of Fel d1 (1105 ng/g) in their clothes compared to the other three groups. (D: 247 ng/g, nCnD: 418 ng/g) but the levels were significantly higher than for all children without a cat at home (345 ng/g, p < 0.05). No concentrations of mite allergen and low concentrations of Fel d1 and Can f1 were found in the children's hair. There were significantly higher concentrations of Fel d1 and Can f1 in dust from curtains than in samples from floors and bookshelves (p < 0.05). There was no significant difference between the allergen concentrations in samples from curtains and from desks and chairs, including the teachers' chairs, the only upholstered furniture in the rooms. Our results support the hypothesis that cat and dog owners bring allergens to public areas in their clothes and support other studies showing that textiles and upholstered furniture function as reservoirs of cat and dog allergens. Thus, children with asthma and other allergic diseases will be exposed to cat and dog allergens at school and by contact with pet owners, even if they avoid animal allergens at home.

Adolescent↗
PubMed1997

Re-examination of incisal tooth wear in children and adolescents.

The material presented in this report was derived from a longitudinal study of the development and progress of incisal tooth wear in children and adolescents. The study group was established in 1991-1992 (baseline examination) and consisted of participants between 8 and 15 years of age. They were re-examined in 1993 (interim examination) and in 1994 (final examination). In all, 77 school children (30 females and 47 males) participated in the three examinations. The timespan between baseline and interim was on average 15 months and the period between interim and final examination averaged 16 months. The total observation period was approximately 32 months. Assessments of incisal wear was made on stone casts using the incisal wear index which was shown to have good reproducibility. The results demonstrated that the prevalence and severity of incisal wear had increased significantly with age. In general the rate of incisal wear progression was higher between baseline and interim than between interim and final examination. In this respect certain differences between the tooth types seemed to exist. At baseline the relationship between age and incisal wear was positive and statistically significant for all tooth types. At the final examination the strength of this relationship had decreased for maxillary and mandibular central and lateral incisors. For canine teeth of both jaws the relationship between age and incisal wear was no longer statistically significant at the final examination.

Adolescent↗
PubMed1997

Relationship between incisal tooth wear and the increasing number of permanent teeth in children and adolescents.

The material presented in this report was derived from a longitudinal study of the development and progress of incisal tooth wear in children and adolescents. The study group was established in 1991/1992 and consisted of 77 participants between 8 and 15 years old. All participants were re-examined in 1994. The interval between the first and second examination was approximately 32 months. Each participant was scored for tooth wear of the anterior teeth of both jaws according to the Incisal wear Index (IwI) and the number of permanent teeth and the tooth types present were recorded at each examination. The results showed that the pattern of incisal wear had been maintained during the observation period. Severity of incisal wear increased as the number of teeth increased. The strength of the relationship between incisal wear and the number of teeth decreased during the observation period. At the same time, the number of teeth and the size of the wear increments were negatively correlated indicating that the rate of wear progression decreased as the number of teeth increased.

Adolescent↗
PubMed1996

Relationship between alignment conditions of teeth in anterior segments and incisal wear.

This report describes the alignment condition and incisal wear of the anterior teeth in individuals 16-19 years of age. Tooth alignment and incisal wear were assessed on casts in accordance with two index systems NONAT (non-aligned tooth) and IwI (incisal wear index). Tests of the methods showed that the reproducibility of the assessments of tooth alignment and incisal wear were satisfactory. The results of the study of tooth irregularity demonstrated that the prevalence of non-alignment of one or more of the anterior teeth were much the same (approximately 50%) for the maxillary and mandibular jaws. The highest frequency was found for the maxillary lateral incisors and the mandibular central incisors (approximately 45%). A relationship between the alignment conditions and incisal wear of the anterior teeth was established. It appeared that non-alignment of one or more teeth in one or both jaws was associated with less severe incisal wear of the anterior teeth. This was most pronounced for non-aligned maxillary central incisors and non-aligned mandibular central incisors.

Adolescent↗
PubMed1995

Longitudinal study of incisal tooth wear in children and adolescents.

This report was derived from a longitudinal study of the development and progress of incisal tooth wear in children and adolescents. The study group was established in 1991/1992 and consisted of 79 participants between 8 and 15 yr. They were reexamined in 1993 and the time span between the first and second examination was 12-14 months. Assessment of incisal wear was made on stone casts based on silicone impression material according to the Incisal wear Index (IwI). The index used was shown to have good reproducibility. The results showed that the pattern of incisal wear had been maintained during the observation period. Prevalence and severity of incisal wear had increased significantly with age. The strength of the suggested linear relationship between age and incisal wear decreased during the observation period. At the same time the growth increments of wear, delta IwI, were negatively correlated with age, indicating that the progression of incisal wear slowed down with increasing age. Description of the true relationship between age and incisal wear outside the age range represented in the sample must await the results of forthcoming studies.

Adolescent↗
PubMed1995

A 2-year follow-up study of incisal tooth wear in dental students.

This report was derived from cross-sectional and longitudinal analyses of prevalence, pattern, and severity of incisal wear in 64 dental students who had virtually complete dentitions at the first examination and unchanged dentitions at the re-examination. They were first examined in 1991 and re-examined after 24 months in 1993. The average age of the students in 1991 was 23 +/- 1.7 years. Assessment of incisal wear was made on stone casts based on silicone impression material in accordance with the Incisal wear Index (IwI). The results showed that the prevalence of incisal wear had not changed during the observation period. The severity of incisal wear for maxillary and mandibular central and lateral incisors had remained essentially the same, whereas the severity of wear of maxillary and mandibular canines had increased during the observation period. There was no statistically significant relationship between age and IwI. The wear pattern found for anterior teeth is discussed in relation to the cuspid protection and the group function theories of occlusion.

Adult↗
PubMed1994

Prevalence, pattern, and severity of incisal wear in dental students.

This paper describes the prevalence, pattern, and severity of incisal wear of anterior teeth in 64 dental students at an average age of 23 +/- 1.7 years with a high number of permanent teeth present. The index used to assess wear on stone casts (IwI) was shown to have good reproducibility. The results indicated that about 98% of the anterior teeth had been worn to various degrees. In both jaws central incisors were most commonly affected by incisal wear, canines followed next in order, and lateral incisors were least commonly affected. Wear of identical teeth on the right and left side tended to be bilaterally symmetrical in both jaws. The results of these initial observations suggest that data from re-examination of this study group will lend themselves to detecting possible changes of the pattern and severity of incisal wear of permanent anterior teeth.

Adult↗
PubMed1992

Adaptation of resin facings to cast gold alloy restorations in the mouth.

The occurrence of marginal spaces between the resin facing and gold alloy framework in 176 crowns and bridge retainers was studied. The restorations were made for canine teeth. The assessment of spaces at the cervical alloy-resin junction was carried out by examining slides of the buccal surfaces taken after application of disclosing agent. Spaces at the incisal alloy-resin junction were assessed by examining resin models under the stereomicroscope. Randomly selected restorations were grouped and examined with reference to length of clinical service (1, 3, 6, and 9 years). The methods were tested for reliability and consistency. The results showed that the frequency of cervical spaces tended to increase with length of clinical service, whereas the frequency of the incisal spaces seemed to remain unchanged. The most severely worn facings had the highest frequency of cervical spaces. In contrast, the least worn facings seemed to have the highest frequency of incisal spaces. For both the cervical and the incisal spaces the highest frequencies were found for relatively long resin facings.

Crowns↗
PubMed1990

Fixed restorations produced for recipients of dental prosthodontic treatment. A comparison between general dental practice and a dental school.

Fixed prosthodontic work ordered by general dental practitioners was examined through registrations made in commercial dental laboratories. A comparison was made with similar data from student files on fixed prosthodontic treatment at the University Clinic in Bergen, Norway, which is located in the same geographic area. The results indicated that the distributional pattern of fixed restorations within the dentition was much the same in the individuals attending the general dental practitioners as in those treated at the dental school. While the practicing dentists preferred metal-ceramics in most cases, most of the restorations inserted at the dental school were based on the metal-resin technique.

Crowns↗
PubMed1990

Dental practitioners' evaluation of the metal-resin and metal-ceramic technique in the treatment with fixed prosthetic restorations.

To collect information on the use of the metal-resin and the metal-ceramic technique, a questionnaire survey among general practitioners was carried out in Bergen, Norway. Of the 20 dentists (16% sample) randomly selected among the private general practitioners, 17 (85%) responded. The results indicated that 45% metal-resin and 55% metal-ceramic constructions were inserted. Metal-ceramic crowns were selected for their favorable esthetics, whereas metal-resin appliances were preferred because of their repair possibilities and good marginal adaptation. Most dentists (70%) claimed that metal-resin restorations have a better marginal adaptation than metal-ceramic constructions. Location in the mouth, the general periodontal condition, and evidence of wear in the remaining dentition also appeared to influence the selection of the type of tooth-colored veneered crown.

Color↗
PubMed1990

Changes over time in the clientele and restoration pattern in a dental school prosthodontic department.

The clientele and the production of single artificial crowns and fixed partial dentures in the Department of Prosthodontics were compared from 1964/68-1982/87. In the first period 65 per cent of the single crowns were made for women versus 55 per cent in the second. In the first period 69 per cent of the crowns were placed in the upper jaw as against 60 per cent in the second period. On average 1.6 crowns were made per female patient in the first period versus 1.4 per male patient. In the second period both sexes averaged 1.8 units. In both jaws the percentage of root-filled crowned teeth had increased in the second period to 60 per cent from 48 per cent in the upper jaw and 46 per cent in the lower jaw. In both sexes maxillary and mandibular teeth were crowned on average 13 years later in the second period than in the first. Sixty per cent of the fixed partial dentures were made for women in the first period versus 55 per cent in the second. In the first period 74 per cent of the bridges were made for the upper jaw as against 70 per cent in the second period. The mean pontic to abutment ratio was 0.7 in both periods. The maximum number of bridges in the first period were made for patients 40-59 years of age versus 50-69 years in the second period.(ABSTRACT TRUNCATED AT 250 WORDS)

Age Factors↗
PubMed1989

Flexural strength of a high-temperature soldered cobalt-chromium alloy.

The flexural strength of a high-temperature soldered cobalt-chromium alloy was compared with that of the intact alloy. In one test group the specimens were soldered by Vitallium welding rods and in the other group Bego cobalt-chromium solder was used. The cylindrical portion of all specimens was mounted equally in an Instron testing machine. No statistically significant differences were found in flexural strength between the groups.

Chromium Alloys↗
PubMed1989

Properties of prosthetic resin-veneer materials processed in commercial laboratories.

Seventeen dental technicians heat-cured microfilled resins, and light-cured hybrid and microfilled resins were used. Marginal adaptation, porosity, hardness, and indentation creep were determined. The results demonstrated considerable variations in all properties studied. The most pronounced variations within the individual brands were found for the properties of porosity and marginal adaptation. When the different products studied were compared, in general the most substantial variations were found for the light-cured specimens. The extremes of number of pores per mm2 were 1.52 and 10.46 for one light-cured product. A moderate scattering of the results of hardness and creep was found. The highly-filled light-cured brands obtained the highest hardness numbers (VHN) and the lowest creep values compared with those of the heat-cured resins. The uneven technical quality found may in part explain the clinical failures of resin facings which are occasionally observed.

Absorption↗
PubMed1987

Porosity of resin veneer materials.

The present investigation has studied the effects of different types of resins and different processing and curing methods on the number and size of pores occurring in resin facing materials. The mean number of pores per square millimeter varied between 0.5 and 4. The highest numbers occurred in unfilled heat-polymerized acrylic resin and in light-activated resin, whereas the lowest numbers were found in heat-polymerized micro-filled resin. Specimens processed in accordance with the free technique and cured under pressure consistently obtained lower numbers of pores than the corresponding specimens processed in a flask. Most of the pores were less than 50 micron diameter in all test groups. From a clinical point of view, a dense resin with a limited content of pores may give the most favorable results in terms of mechanical, esthetic, and hygienic properties of the veneer.

Acrylic Resins↗
PubMed1985

Marginal adaptation of resin veneers to gold castings.

The magnitude of the fissures between resin facing materials and gold castings was measured by light microscopy. Two different products and two different processing procedures were used. The effect of water sorption on the fissure size was also studied. Mean fissure sizes varied between 3 and 25 microns. The best adaptation between the resin material and the gold alloy was obtained by the conventional closed flasking technique compared with free processing in a pressure vessel. When processed by closed flasking the product that did not contain microfiller showed fissure widths approximately one fourth of those resulting from the open processing technique. The other product, containing microfiller, was less sensitive with regard to processing. The effect of water sorption on the fissure width was most evident in the test groups containing specimens processed in flask.

Chemical Phenomena↗