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Biomedical subjects

U Zappa

Publications and source records attributed to U Zappa.

30 records · Page 2Linked to original sources
PubMed1991

Root substance removal by scaling and root planing.

The amount of root substance removed by scaling and root planing is largely unknown. The present study evaluated in vitro the root substance loss caused by a defined number of working strokes at known forces. Forty extracted teeth with loss of connective tissue attachment into the middle third of the roots were washed and embedded in plaster, leaving one entire corono-apical tooth aspect exposed. The teeth were reproducibly repositioned in a bench-vise, where a profilometer repeatedly measured root surface levels at the same location. In a standard area of the roots a total of 40 working strokes were applied. Low forces were used in 30 teeth and high forces in 10 teeth. The forces were recorded using a piezo-electric receiver built into the upper shank of the curet. Root substance loss was measured after 5, 10, 20, and 40 working strokes. The results showed that the mean low force used per working stroke across all 40 strokes was 3.04 Newtons for the low forces, and 8.48 Newtons for the high forces. Mean cumulative loss of root substance across 40 strokes was 148.7 microns at low forces, and 343.3 microns at high forces. The mean force per stroke increased slightly across the 40 strokes, while substance removal per stroke decreased. Substance removal per stroke during strokes 1 to 5 was 6.8 microns using low forces and 20.6 microns using high forces. During strokes 21 to 40 mean removal per stroke was 2.3 microns at low forces, and 5.6 microns at high forces. These results suggest that high forces remove more root substance, and loss per stroke becomes less with increasing numbers of strokes.

Dental Scaling↗
PubMed1991

In vivo scaling and root planing forces.

The purpose of the present study was to assess the scaling and root planing forces exerted in vivo. Ten dentists and 10 dental hygienists scaled and root planed one aspect of an incisor in an adult patient with untreated advanced periodontitis. During scaling and root planing forces were recorded using a piezo-electric receiver, an electronic transducer, and an analogous writer. The forces were recorded in mA and converted into Newtons (N). The results showed that the mean scaling force applied by dentists was 5.70 N and ranged between 1.01 to 10.35 N. The corresponding values for dental hygienists were a mean of 5.38 N, and a range of 1.52 to 15.73 N. The root planing forces in dentists reached a mean of 4.62 N, and ranged between 0.86 to 8.88 N. For hygienists, these values were 4.58 N with a range of 1.56 to 10.59 N. Negative forces impacting on the periodontal soft tissues were also recorded. They were not present in all therapists, but consistently at work within specific therapists. During scaling these forces reached a mean of -0.40 N in dentists and -0.47 N in dental hygienists. During root planing, these forces were mean -0.59 N in dentists, and -0.81 N in hygienists. There were no statistically significant differences between scaling forces and root planing forces, nor between forces used by dentists and hygienists (P greater than 0.05). However, there were significant differences between the force levels of the individual therapists for all positive forces (P = 0.0001), and for negative forces during root planing (P = 0.0001). The technology and information provided by this investigation may enable studies evaluating clinical effectiveness of scaling and root planing doses.

Adult↗
PubMed1991

[Effect of electrically powered dental devices on cardiac parameter function in humans].

Electrically powered devices represent a hazard for patients with cardiac pacemakers. The aim of the present investigation was an in vivo evaluation of possible interactions between electrically powered dental instruments and the function of artificial pacemakers in humans. In 26 patients with artificial pacemakers, different dental instruments were applied, including air scaler, ultrasonic curets, electric pulp tester and electrotome. These devices were applied at highest intensity. Immediately prior to, during, and immediately after applications of these instruments, the pulse rate and the electrocardiogram (EKG) were recorded. The EKG recordings were assessed for irregularities in the distances between the pacemaker peaks. The dental devices were assessed for magnetic fields or induction tension. The results showed that none of the dental devices caused an irregularity in the pacemaker function. The air scaler, Piezon ultrasonic curet and the electric pulp tester caused no measurable magnetic fields. The Sonus 2 ultrasonic curet and the electrotome magnetic fields were measured up to 60 and 50 cm, respectively. All dental devices caused induction tension. The highest value was produced by the electrotome. It seems that cardiac pacemaker function is not affected by electrically powered dental devices. However, there remains a risk in relation to older pacemakers or defective dental devices.

Adult↗
PubMed1991

[Episodic progression of periodontitis--histologic associations].

Periodontal lesions are primarily diagnosed using the periodontal probe. Using site-specific probing attachment level measurements in defined time intervals, dentists can identify patients and dentition segments that suffer temporarily from a high periodontitis progression rate. The present article describes whether sites where clinical measurements suggested a high progression rate had tissue characteristics different from nonprogressing sites. Ten patients with untreated advanced adult periodontitis were monitored for 10 months by measuring clinical parameters every 30 days. These parameters were gingival index, plaque index, bleeding index, bleeding on probing, probing depth and probing attachment levels. Every month pairs of contralateral sites were sought where one site had lost 2 mm (P-2) or more (P greater than 2) probing attachment (P-sites) and the other site had not (C-site). From these sites supracrestal soft tissue biopsies were taken. After histological processing, a first analysis determined the number of inflammatory cells in 9 standard areas in P- and C-biopsies. A second analysis evaluated cell populations at the apical end of the junctional epithelium. The results showed that bleeding on probing, probing depth and probing attachment loss were statistically significantly greater at P-sites. At C-sites there were only few inflammatory cells. At P-2-sites there were numerous inflammatory cells, and in P greater than 2-sites the number of these cells was statistically significantly greater than in corresponding control sites. The cell populations at the apical end of the junctional epithelium were different between P- and C-sites. At P-sites, the percentage of mast cells, monocytes/macrophages and plasma cells was statistically significantly greater than at C-sites. At C-sites, the percentage of fibroblasts was statistically significantly greater than at P-sites. These results demonstrate that clinical probing identifies episodes of periodontitis progression, which are associated with pronounced changes in tissue characteristics, namely greater numbers of inflammatory cells.

Dental Plaque Index↗
PubMed1991

Episodic probing attachment loss versus pocket depth: bacterial morphotype associations.

Marginal periodontitis in humans is characterized by phases of clinical disease progression, which are interspersed between periods of quiescence. The purpose of the present study was to compare subgingival bacterial populations from periodontal sites undergoing episodic probing attachment loss with bacterial populations from non-progressing lesions. Probing depth and attachment levels were measured in 10 adult patients at baseline, and every 30 days thereafter for 10 months. Pairs of corresponding contralateral sites were identified where one site had lost probing attachment within the previous month (P) and the other site had not (C). Subgingival bacterial samples were obtained from these sites and analyzed using darkfield microscopy. Motile forms, spirochetes, curved and straight rods, filaments, coccoid cells, fusiforms, and the total number of bacteria were assessed. The results showed that median pocket depth and attachment change were statistically significantly greater in P-sites as compared to C-sites. There was no significant difference in bacterial populations between P- and C-sites (p greater than 0.15). Motile forms, spirochetes, and total number of bacteria were positively correlated with pocket depth in P-sites, while in C-sites the same was true only for curved rods. These results suggest that darkfield microscopy of subgingival bacteria in humans represents primarily pocket depth.

Adult↗
PubMed1990

Comparison of serological and DNA probe analyses for detection of suspected periodontal pathogens in subgingival plaque samples.

Several methods are currently being used to identify specific bacteria in dental plaque, namely direct culture, serological techniques and DNA probes. Culture methods are labour-intensive, dependent on the viability of the cells, and require fastidious growth conditions. Serological and DNA probes allow rapid strain-specific identification of periodontal pathogens with limited effort. The purpose of the present study was to compare results from serological and DNA probes in assessing and quantitating the presence of three suspected periodontal pathogens in subgingival plaque: Actinobacillus actinomycetemcomitans, Bacteroides gingivalis and Bact. intermedius. Subgingival bacterial samples were obtained from 4 periodontal sites of each of 13 patients with untreated moderate to advanced adult periodontitis. Samples were taken using 2 paper points that were simultaneously inserted for 10 s to the bottom of the periodontal pockets. The plaque from one paper point was analysed by immunofluorescence using monoclonal antibodies. The other sample was analysed by species-specific cloned DNA probes. The number of bacteria per millilitre was calculated for both methods, and used for comparisons of results obtained with the two techniques. Results from indirect immunofluorescence and DNA hybridization analyses were negative for A. actinomycetemcomitans across all samples. Fluorescence did not detect bacteria at levels lower than 10(4), while the DNA probes identified organisms at levels of 10(3). Similar numbers of samples positive for Bact. gingivalis were obtained with either method (p = 0.227), and the results were not independent. A significantly greater proportion of Bact. intermedius-positive samples was detected by immunofluorescence (p = 0.0039), and the results of immunofluorescence and DNA hybridization were independent.(ABSTRACT TRUNCATED AT 250 WORDS)

Actinobacillus↗
PubMed1990

Episodic probing attachment loss in humans: histologic associations.

Marginal periodontitis in humans is characterized by episodes of probing attachment loss followed by periods of quiescence. The purpose of the present study was to assess characteristics of the inflammatory infiltrate in periodontal lesions where episodic probing attachment loss had occurred within the previous month. In 10 systemically healthy adult human subjects with untreated advanced periodontitis, probing attachment levels were measured at baseline and every 30 days thereafter for 10 months. Measurements were made at six sites of every tooth using an acrylic onlay as a reference point and a pressure sensitive probe. Sites where double measurements confirmed that probing attachment loss of 2 mm or more had occurred within the previous month were identified (P-sites), as were corresponding contralateral non-progressing sites (C-sites). Biopsies of the supracrestal tissues were taken from these sites, processed, and cut in 1 mu sections for histologic evaluation. Counts of inflammatory cells in standard areas of the sections were compared between P and C sites. The results indicated that 5.04% of 1566 sites under investigation lost probing attachment during the 10-month observation period. Inflammatory cell counts were higher in P-sites as compared to C-sites. P-sites with more than 2 mm attachment loss (P greater than 2 sites) had significantly more inflammatory cells within standard areas at the apical end of the junctional epithelium than non-progressing C-sites (P less than 0.02). There was no significant difference in counts between P-sites progressing 2 mm (P-2 sites) and corresponding C-sites.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1990

[The episodic progression of untreated adult periodontitis].

Marginal periodontitis in humans and animals is characterized by site-specific episodes of accelerated clinical attachment loss, which are interspersed between periods of quiescence of variable length. Diagnosis of episodic periodontitis progression could allow for early interception and arrest of progression. Currently available diagnostic techniques are not sensitive enough to detect phases of periodontitis progression. Diagnostic tests should be developed which are sensitive and practical enough to determine need and success of periodontal treatment at specific sites or sections of a dentition. In a longitudinal study on untreated periodontitis in humans, progressing and nonprogressing periodontal lesions were identified and investigated using clinical, microbiological, histological and immunohistochemical methods. Ten adult patients with untreated advanced periodontitis were monitored monthly for ten months. Attachment levels and probing depth were determined at six sites of every tooth. Corresponding contralateral sites were identified where one site had lost 2 mm or more probing attachment since the previous session (P-site), and the other site had not (C-site). The results showed that bleeding on probing was positively and statistically significantly correlated with episodic clinical attachment loss. The error in probing attachment level measurements varied with the tooth type and was greatest at molars. Over time the measurement error became smaller. In deeper pockets the probing error was greater than in shallow pockets. It appears that in order to accept clinical progression of periodontitis an increase in probing attachment loss or probing depth of more than 2 mm has to be observed. Using the mean attachment loss per site in a dentition at six or nine months after initial measurements should enable the dentist to discriminate patients with a higher rate of periodontitis progression from patients with a low rate. Darkfield microscopy used for assessment of subgingival bacterial populations seems to be without diagnostic value for differentiation between P- and C-sites.

Epithelial Attachment↗