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Biomedical subjects

P Hotz

Publications and source records attributed to P Hotz.

At least 55 records · Page 3Linked to original sources
PubMed1993

[Dental caries (DMFT) in adults in Switzerland 1988].

In 1988, 864 adults were examined for dental and periodontal conditions in 47 dental offices in Switzerland according to WHO methods. Among the 57 offices selected at random 10 dentists were unwilling to cooperate. Within each office, 36 patients were chosen by a randomizing mechanism. 51 percent of the selected patients presented themselves for the examination whereas 14 percent refused to participate in the study; of the remaining subjects one third could not be reached during the three to five days available for contacting them and two thirds were unable to come to the respective dental office at the preset day of examination. The DMF data obtained were similar to the results of previous local surveys, part of which were based on random samples. Up to age 74, it was concluded that the data of the present survey are fairly representative of the Swiss resident population. In the age group 75 and above, the number of missing teeth (MT) was too low, mainly due to edentulous persons, institutionalized and other, being obviously underrepresented. The Swiss DMFT of 22.3 in the age group 35-44 was almost the highest mean among 26 European countries. However, prevention efforts at school age, already obvious in the age group 30-34, will substantially improve the results at age 35-44 by the year 1998. The number of DT was 1.0 and 1.3 for the ages up to 29 and below 1.0 in the older groups. Up to age 54, FT was the most important component of the DMFT while in the older groups, MT was highest.

Adult↗
PubMed1993

Epidemiology and risk factors of wedge-shaped defects in a Swiss population.

The purpose of this study was to determine the prevalence of wedge-shaped abrasion defects in the teeth of an adult Swiss population. 980 letters explaining the study were sent to randomly selected subjects. 391 persons (40%) belonging to two age groups (26-30 and 46-50 years) were checked for frequency and severity of wedge-shaped lesions on all buccal tooth surfaces. Furthermore patients were asked about dietary and prophylactic habits as well as other factors possibly relevant to this study. The frequency of severe wedge-shaped defects was 19.1% in the younger, and 47.2% in the older age group, with a mean of 3 affected teeth per person (pooled age group). On average, 34.8% of all patients suffered from tooth hypersensitivity. 84.6% of the examinees with wedge-shaped defects complained of hypersensitivity at these sites. It is concluded that wedge-shaped defects cause considerable problems to more than one third of the population, and that such lesions are often combined with hypersensitivity of affected teeth.

Adult↗
PubMed1992

Smell or taste disturbances, neurological symptoms, and hydrocarbon exposure.

A total of 264 workers participated in a cross-sectional study concerning the toxicity of hydrocarbons. The clinical examination shows an increased prevalence of smell and/or taste disturbances in the heavily exposed group. These symptoms appear to be generally transitory and reversible. They seem to be due to concentration peaks rather than to a long exposure duration. They are associated with acute depressor effects and not with symptoms which could belong to a hydrocarbon-induced chronic toxic encephalopathy.

Adult↗
PubMed1992

Effectiveness of three cavity varnishes in reducing marginal microleakage of amalgam restorations: an in vitro study.

Dentin Adhesit, Cavi-Line and Kavite Lak cavity varnishes were applied to the walls of prepared Class V cavities in fifty-two caries free extracted molar teeth before placing amalgam fillings. Tests with Methylene Blue dye after thermocycling showed that all cavity varnishes showed significantly lesser marginal leakage when compared with the control group without any cavity varnish.

Dental Amalgam↗
PubMed1992

[The effect of 2 finishing methods on the micromorphology of the proximal box margin. An in-vivo study].

Minipreparations of class II cavities often are not employed in daily practice mainly because adequate instruments for finishing the axial box margin and the proximo-cervical curvature were not available. The purpose of this in vivo study was to assess the morphology of the proximal box margin after finishing with two different methods. 81 class II minicavities for amalgam restorations were prepared by 4 dental practitioners. One method for finishing the axial box margin and the proximo-cervical curved border was the use of a modified EVA-System with the total amplitude reduced to 0.4 mm and a highly flexible file (Cavishape, grain 25 microns). The other method was the use of an axial margin trimmer. The micromorphology of the two methods was investigated by means of scanning electron microscopy and a score system as described earlier (Lussi et al. 1987). The margins of the axial box as well as of the proximo-cervical curvature were significantly better finished with the EVA-System and the highly flexible file compared to the axial margin trimmer (p < 0.001). The finishing time for the box margin was not significantly different using the EVA instrument or the axial margin trimmer. These findings confirm other in vitro investigations. This in vivo study shows that the modified EVA instrument with the highly flexible file (Cavishape, grain 25 microns) is clearly superior to the axial margin trimmer in finishing the box margin. This device allowed a significant better finishing of the axial box margin and the proximo-cervical curvature of minicavities in daily practice.

Chi-Square Distribution↗
PubMed1992

[The preparation of enamel margin beveling in proximal cavities].

Minicavities for posterior composite resin restorations were prepared in 24 caries-free teeth. The aim of this in vitro study was to evaluate the micromorphology of the proximal cavosurface bevel. The cavosurface bevel has been employed for many years as an accepted modification for composite restorations in permanent anterior teeth. The bevel provides more exposed enamel rod ends available for bonding. Using the acid-etch technique the resin-enamel bond is stronger with etched transverse sections of enamel prisms than with longitudinal sections. Enamel in the proximal and gingival wall of class II cavity preparations for restoration with composite should be beveled because prism direction is at right angles to the surface. The aim of this study was therefore to compare two methods for beveling the box margins of small proximal cavity preparations. One method for the preparation of the proximal bevel was the use of a modified EVA-System with the total amplitude reduced to 0.4 mm, the fixation of the file position and a new developed file (Bevelshape, grain 40 microns). The form of this file was modified in order to produce a short cavosurface bevel of the gingival and proximal wall without danger of damaging the adjacent tooth. The other method was the use of an axial margin trimmer. The micromorphology of the two methods was investigated by means of scanning electron microscopy and a score system as described earlier (Lussi et al. 1987). Statistical analysis revealed significant differences between the two groups. As compared to the axial margin trimmer the new device allowed a significant better finishing of the proximal bevel (p < or = 0.001).(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Caries↗
PubMed1992

[The modification of the polymerization of composite materials by eugenol-containing temporary fillings].

The objective of this study was to evaluate the influence of eugenol-containing temporary fillings on the polymerisation of composite materials. Cavities of 2 mm in diameter and 2 mm in depth were prepared in enamel as well as in dentine. Immediately after preparation the cavities of the control group were filled with a light curing composite, a chemical curing composite, or a light and chemical curing composite. The cavities of the experimental group were filled with Nobetec (temporary filling material containing zinc-oxide-eugenol). After six weeks, the Nobetec fillings were removed by means of an excavator, the cavities were cleaned with water and filled with one of the above six composites. The specimens were embedded in Epofix and afterwards cut through the center of the filling. The cut surfaces were polished to 3 microns and afterwards (> 4 days) the hardness was measured with a Knoop hardness testing machine at different distances from the cavity wall. The results of the control group and of the experimental group were compared statistically. The polymerisation of five of the six materials was not inhibited by a temporary filling material containing zinc-oxide-eugenol. The difference in hardness for Brilliant Lux (light curing) was fer-highly significant (p < 0.001) between 0 micron and 100 microns from the cavity margin, if the cavity was first filled with a temporary filling material, containing zinc-oxide-eugenol. The results show that there exist certain composite filling materials that are inhibited in their polymerisation by the tested eugenol containing temporary filling material.

Composite Resins↗
PubMed1992

[Toxic substances at the work place: do occupational diseases still occur in Switzerland?].

The statistics about work-related diseases influence greatly the setting of prevention priorities. It is consequently of prime importance that these statistics correctly mirror the reality. This paper summarizes the results of studies which show that the real prevalence of work-related diseases is probably two to three times greater than generally admitted; therefore, it seems very important to improve the quality of diagnosis and of data collection.

Humans↗
PubMed1992

[The release of mercury and copper from in vivo aged amalgam fillings].

Release of mercury and copper in water over time from in vivo annealed amalgams in an unpolished and polished state was measured. Mercury and copper loss from unpolished amalgams was on the average 1,00 micrograms/cm2.d and 0.06 micrograms/cm2.d, respectively. Polishing the amalgams reduced these values significantly to 0.19 micrograms/cm2.d for mercury (p = 0.004) and to 0.03 micrograms/cm2.d for copper (p = 0.009). It was concluded that polishing amalgam surfaces (under water cooling) reduces release of mercury and copper significantly.

Copper↗
PubMed1991

Musculoskeletal and skin disorders in a population of floor-layers.

In the frame of a study on hydrocarbon-induced toxic effects, the knee morbidity and the prevalence of work-related arthralgias, gonalgias, myalgias and skin anomalies were investigated in a group a floor-layers. The results show that a previous history of knee morbidity is distinctly higher in floor-layers and that these workers have a higher prevalence of musculoskeletal and cutaneous disturbances than the comparison group. Owing to the fairly high prevalence of these troubles, it seems that this pathology deserves more attention and that more efficient preventive measures are indicated.

Adolescent↗
PubMed1991

Comparison of the sealing ability of four cavity varnishes: an in vitro study.

The purpose of this study was to test and to compare, in vitro, the sealing ability of four different cavity varnishes used to minimize the marginal leakage of amalgam fillings. For this purpose, a model was developed in order to avoid quality-deteriorating effects (such as condensation forces used during placement of amalgam) and temperature changes. In this model, raw ceramic disks were used instead of dentin. The four varnishes showed significant reducing effect on the penetration of the dye (Methylene Blue) compared with the control. There was no cavity varnish with optimal sealing.

Analysis of Variance↗
PubMed1991

Dental erosion in a population of Swiss adults.

The purpose of this study was to determine the prevalence of dental erosion in an adult population in Switzerland. 391 randomly selected persons from two age groups (26-30 and 46-50 yr) were examined for frequency and severity of erosion on all tooth surfaces. Information was gathered by interview about lifestyle, dietary and oral health habits. For facial surfaces 7.7% of the younger age group and 13.2% of the older age group showed at least one tooth affected with erosion with involvement of dentin (grade 2). 3.5 teeth per person in the younger and 2.8 teeth per person in the older age group were affected. Occlusally, at least one severe erosion was observed in 29.9% of the younger and 42.6% of the older sample with 3.2 and 3.9 erosion-affected teeth per person, respectively. 3.6% of the younger age group and 6.1% of the older age group showed slight lingual erosion on the maxillary anterior teeth. Severe lingual erosions were scarce. Data from interviews and multiple regression analyses revealed that acids from beverages are significantly associated with presence of erosion.

Adult↗
PubMed1991

Glycosaminoglycans, albuminuria and hydrocarbon exposure.

The value of the glycosaminoglycans (GAG) determination in urine was examined in a population of hydrocarbon-exposed workers and compared to the usefulness of the fractional albumin clearance (FAC). Blood pressure and hydrocarbon exposure interact to increase the FAC but the GAG concentration seems less useful because too many other variables influence it as well.

Adolescent↗
PubMed1990

[Glomerular erythrocytes, albuminuria, glycosaminoglycans and exposure to hydrocarbons].

As part of a study on the possible nephrotoxicity of hydrocarbons, the urinary erythrocyte concentration and the percentage of glomerular erythrocytes were assessed. Albumin excretion rate, glycosaminoglycan and retinol-binding protein concentration, and N-acetyl-beta-glucosaminidase activity were measured simultaneously. The results show that the erythrocyte concentration and the percentage of glomerular erythrocytes tend to increase with hydrocarbon exposure, and that a nephrotoxic effect of occupational hydrocarbon exposure deserves consideration.

Acetylglucosaminidase↗
PubMed1990

Hydrocarbon exposure, hypertension and kidney function tests.

Control and hydrocarbon exposed workers participated in a cross-sectional study about the nephrotoxicity of chronic hydrocarbon exposure. Different markers of glomerular and tubular function as well as the celluria were examined and compared. The results show that the interaction between hypertension and hydrocarbon exposure has an influence on the kidney function. For the clearance the interaction age-exposure seems to play a more important role than age or exposure alone. The most useful markers appear to be the albuminuria, the N-acetyl-beta-D-glucosaminidase activity, the retinol-binding-protein concentration and the creatinine clearance.

Adult↗
PubMed1990

Mercury and copper release from amalgams in different soft drinks.

Release of mercury and copper over time from three different non-gamma-2 amalgams in a polished and unpolished state was tested in water and two soft drinks. The measuring methodology was geared to warrant minimum Hg losses due to evaporation and adsorption. Initial (24 h) values for Hg and Cu were relatively high in water, but were much lower in the soft drinks. The 24-104-hour values were much lower than the initial readings for all amalgams and all environments. Polishing reduced leaching--significantly, however, only in water and for only two of the three amalgams. The lower values in the soft drinks and over time could be due to passivation of the amalgam. Passivation appears to be time-dependent and chemically influenced by the environment.

Carbonated Beverages↗