Biomedical subjects

B Hugo

Publications and source records attributed to B Hugo.

13 recordsLinked to original sources

PubMed1995

[A mathematical model for the treatment of root surfaces with rigid and flexible instruments].

The objective of this study was to assess the accessibility of root surfaces using stiff instruments in order to evaluate the advantages of a new flexible instrument-set for the treatment of periodontally diseased roots. 100 extracted human teeth were sectioned and histologically prepared. They were divided into two groups each containing 50 sections. Group I showing the interproximal, group II the buccal/lingual morphology. Slides were taken of each section under a constant magnification (3.2x) and a selected number of distances and angles were measured on each section. Using trigonometric functions the following parameters were calculated and set in relation with hypothetical probing depths ranging from 0-15 mm: 1.) instrument length; 2.) change of the instrument angulation; 3.) theoretical deflection of the gums. Statistical analysis was performed using Student's t-test. For a given probing depth the instrument length was independent of the sites and the deflection of the gums. When a deflection of the gums was assumed, the instrument angulation was constant; an exponential decrease of the angulation with increasing probing depth was found with gum deflection. The deflection was increasing with increasing probing depth, showing statistically significant differences between interproximal and buccal/lingual sites (p < or = 0.05). In conclusion the instrument length seems not to be an impeding factor for the accessibility of root surfaces in contrast to the instrument angulation and the fact that teeth are encircled by the gum. Due to morphological reasons stiff instruments seem to be inferior to flexible instruments when a non-surgical root treatment is performed.(ABSTRACT TRUNCATED AT 250 WORDS)

Dental Scaling↗

PubMed1995

[Personnel and instrumental differences in the treatment of root surfaces. A comparison on a phantom model].

The treatment of root surfaces in periodontal lesions with mechanical instruments is becoming more and more popular as an alternative to the conventional treatment with curets. In this in-vitro study a phantom head with a simulated periodontitis was used. The aim of this investigation was to determine the percentage of the subgingival non-treated root surfaces after treatment with different instruments and by different persons. Newly developed mechanical file instruments (Rootshape) were tested. Hand curets served as control group. The treatment of the teeth was carried out by three groups, each including 4 people. Group one were dental hygienists (DH), group two dentists with (Spez) and group three dentist without (Zaz) experience in the therapy of periodontal diseases. They were asked to perform a scaling and root planing on six teeth (16, 21, 24, 36, 41, 44) both with curets and Rootshape files. The size of the non-treated areas was subsequently determined planimetrically and expressed as percentage of the entire subgingival root surface. Independent of the group the percentage after file treatment was significantly lower (mean 9.85 +/- 7.78%) than that after curet-treatment (mean 14.74 +/- 10.20%). Significant differences were found when the three groups were compared after treatment either with files or curets (DH 9.61 +/- 8.02%, Spez 12.11 +/- 8.01%, Zaz 15.18 +/- 11.01%; p < 0.001). Zaz working with files achieved as good results as DH or Spez with curets (p < or = 0.05). The results indicate that the files represent an alternative to hand instruments concerning the accessibility of root surfaces.

Dental Hygienists↗

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 status of the dentition in 2 Swiss population groups before the introduction of refined sugar].

Caries and parodontitis have been one of the most spread diseases of mankind. In an archaeological study, 53 graves of Bernese patricians were exhumed. 22 skulls of adults with 392 teeth were examined. They lived between the 16th and the 18th century in the community of Worb BE. In some cases identification could be accomplished by comparison of oil paintings with skulls, using a computerized technique. The aim of this study was to evaluate the prevalence of caries, the loss of periodontal bone, the amount of calculus and of abrasion. To compare the dental situation with another population segment sex- and age-matched dates were used. This second population segment lived between the 12th and 18th century and belonged to a lower social class than the patricians from Worb. The comparison of these two groups showed significant differences only in the abrasion pattern. We conclude that the social class did not significantly influence most of the parameters studied here. The different abrasion pattern could be due to different dietary habits.

Alveolar Bone Loss↗

PubMed1991