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Biomedical subjects

A F Hefti

Publications and source records attributed to A F Hefti.

At least 19 recordsLinked to original sources
PubMed2000

Treatment with subantimicrobial dose doxycycline improves the efficacy of scaling and root planing in patients with adult periodontitis.

BACKGROUND: In a previous study, subantimicrobial dose doxycycline (SDD) significantly improved clinical parameters associated with periodontal health in patients with adult periodontitis (AP) when used as an adjunct to a maintenance schedule of supragingival scaling and dental prophylaxis. In this double-blind, placebo-controlled, parallel-group, multicenter study, the efficacy and safety of SDD were evaluated in conjunction with scaling and root planing (SRP) in patients with AP. METHODS: Patients (n = 190) received SRP at the baseline visit and were randomized to receive either SDD 20 mg bid or placebo bid for 9 months. Efficacy parameters included the per-patient mean changes in clinical attachment level (CAL) and probing depth (PD) from baseline, the per-patient percentages of tooth sites with attachment loss (AL) > or = 2 mm and > or = 3 mm from baseline, and the per-patient percentage of tooth sites with bleeding on probing. Prior to analysis, tooth sites were stratified by the degree of disease severity evident at baseline RESULTS: In tooth sites with mild to moderate disease and severe disease (n = 183, intent-to-treat population), improvements in CAL and PD were significantly greater with adjunctive SDD than with adjunctive placebo at 3, 6, and 9 months (all P <0.05). In tooth sites with severe disease, the per-patient percentage of sites with AL > or = 2 mm from baseline to month 9 was significantly lower with adjunctive SDD than with adjunctive placebo (P<0.05). Improvements in clinical outcomes occurred without detrimental shifts in the normal periodontal flora or the acquisition of doxycycline resistance or multiantibiotic resistance. SDD was well tolerated, with a low incidence of discontinuations due to adverse events. CONCLUSIONS: The adjunctive use of SDD with SRP is more effective than SRP alone and may represent a new approach in the long-term management of AP.

Adult↗
PubMed1999

Measurement of clinical attachment levels using a constant-force periodontal probe modified to detect the cemento-enamel junction.

The handpiece of a Florida sleeve probe was modified to create a flange with the capability to detect the cemento-enamel junction (CEJ). This new instrument (the Pressure-controlled, Automated, Standardised Handpiece or Florida PASHA probe) was used to determine whether (a) the CEJ could be reproducibly detected in dried, human skulls and (b) clinical attachment levels could be reliably measured in human subjects. When using the Florida PASHA probe to detect the CEJ at 157 different sites in four dried, human skulls, there were no statistically significant (p > or = 0.15) differences in mean CEJ detection measurements for any of the three participating examiners; either when the CEJ was visualised or obscured. The mean differences between first and second replicates ranged from 0.00 to 0.08 mm. Intraclass correlation coefficients (ICCs) of repeated measures in both conditions ranged from 0.70 to 0.83 for tactile CEJ detection (CEJ obscured), and from 0.95 to 0.96 for visual detection (CEJ visible). In human studies, the Florida PASHA probe was used by two examiners to determine clinical attachment levels (CAL) at 660 sites in 5 human subjects undergoing supportive periodontal therapy. Intra-examiner agreement of replicate measurements recorded by the probe, as measured by calculating ICCs, ranged from 0.79 to 0.85 for the 2 examiners, respectively. A statistically significant inter-examiner difference in mean CAL measurements when using the Florida PASHA probe was found (p<0.001). Notwithstanding this difference, inter-examiner agreement was good, with an ICC of 0.83. These data suggest that the Florida PASHA probe can reproducibly detect the CEJ and is proposed as a tool for measuring CAL in humans.

Alveolar Bone Loss↗
PubMed1999

Cost-effective design for dental randomized clinical trials with longitudinal observations.

In general, randomized clinical trials (RCT) in dentistry involve longitudinal observations. In such studies, the total cost is a function of the number of study subjects and visits, the study duration, and the type and number of examinations at each visit. In this paper, we derived the minimum cost design for longitudinal RCTs with 2 treatment arms and multiple visits. We optimized the number of subjects, visits and repeated measurements under the constraints of the requirements for statistical significance, power and minimum total study cost. A SAS macro was written and made available on the World Wide Web, so interested clinical investigators can easily find optimal designs. The application of the program is illustrated using an example.

Cost-Benefit Analysis↗
PubMed1998

Cyclosporin A and hydroxycyclosporine (M-17) affect the secretory phenotype of human gingival fibroblasts.

The responsiveness of human gingival fibroblast populations to cyclosporin A (CsA) and its principal metabolite, hydroxycyclosporine (M17), was evaluated in cell culture. Gingival fibroblasts exhibited a dose-dependent accumulation and bell-shaped distribution of dansylated CsA. A 100-fold excess of non-labeled CsA prevented the accumulation of the fluorescent probe in the fibroblasts. Both CsA (400 ng/ml) and M17 (100 ng/ml) stimulated mean gingival fibroblast cell number to 23.2% and 36.7% above controls, and reduced mean collagen production by 37.7% and 37.4% below controls, respectively; however, neither CsA nor M17 affected mean protein production in comparison to control cultures. Analyses of responses to CsA and M17 by ligand-accumulating and non-accumulating fibroblasts sorted out from the parent cultures did not provide consistent interstrain responses either by cells representing the upper quartile of fluorescence or cells representing the bottom quartiles of fluorescence. These data demonstrate that CsA is accumulated by gingival fibroblasts and that CsA and M17 are potent modulators of gingival fibroblast phenotype.

Adolescent↗
PubMed1997

Evaluating the merits of option-3 methods in relative attachment level measurement in a healthy population.

Attachment loss is the principal clinical indicator for periodontal disease progression. However, the attachment measurement can be inaccurate due to outliers. A remedial scheme, the option-3 scheme, has been suggested in the literature. This scheme involves first measuring the relative attachment twice at any given site. A third measurement is required if there is a large disagreement between the first two probings. When the third measurement is taken, there are several possible ways to make the final assessment of the true attachment level. Among them are the average of the 3 measurements, the average of the closest 2, and the median of the 3. This report evaluates the merits of the option-3 scheme by comparing it with other schemes to reduce measurements variance and outliers. Since true attachment levels are unknown, we chose to check accuracy through measurement consistency between visits in healthy subjects using the fact that such subjects should have little real change in attachment levels. 12 healthy subjects participated in the study. They visited the clinic 4 times in 4 months. Two types of the Florida stent probe were used by 2 calibrated examiners. It was found that option-3 schemes were more accurate than a single probing or duplicate probings in estimating the relative attachment level. The 3 final assessment schemes performed almost equally well from a practical standpoint, but the median was the best among them in a statistical sense.

Adult↗
PubMed1997

Periodontal probing.

For decades, probing clinical pocket depth and attachment level have been recognized as the dentist's most important tools in diagnosing periodontal health and disease. They are physical methods to measure the distance from the bottom of a pocket to a reference line, usually the gingival margin or the cemento-enamel junction. Probing accuracy and precision are affected by factors like the design of the probe, probing force, probe position, pocket depth, or tissue inflammation. Recently, several new electronic periodontal probes have been developed. They feature high instrument precision, allowing for measurements to the nearest tenth of a millimeter. They control for probing force and permit data to be collected and stored electronically. The purpose of this review paper is to summarize various aspects of periodontal probing. First, the history of periodontal probes will be briefly recollected, and interesting and significant inventions of the past and the present emphasized. Then, the importance of the periodontal tissues relative to probe tip penetration will be reviewed, and the probing performance will be discussed. The paper will conclude with notes on selected statistical issues.

Dental Instruments↗
PubMed1996

Light source-induced error in computer-assisted image analysis with a video-based system.

OBJECTIVE: We tested the hypothesis that two different light sources, an alternating current fluorescent viewbox and a direct current halogen viewbox, do not differ with respect to their ability to illuminate reproducibly a radiograph during image capture. STUDY DESIGN: Two radiographs were taken: one with four hydroxyapatite chips mounted against a dry mandible and one without the chips. They were digitally subtracted with a video-based imaging system. The procedure was repeated at different times. RESULTS: A statistically significant difference among optical density measurements was found when the alternating current fluorescent viewbox (p < 0.001) was used and was related to light intensity variation. Such effect was not observed with the direct current halogen viewbox (p = 0.873). CONCLUSION: Study design efficiency was increased by 212% with the use of the direct current halogen viewbox so that to detect a specified treatment effect with a given level of statistical confidence, the sample size has to be 2.12 times greater if the alternating current fluorescent viewbox is used.

Absorptiometry, Photon↗
PubMed1995

Sonic and ultrasonic scalers in a clinical comparison. A study in non-instructed patients with gingivitis or slight adult periodontitis.

In the present study, the Cavitron 2002 ultrasonic scaler was compared with the Titan-S air scaler in 20 subjects with gingivitis or slight periodontitis, whereby the majority of the patients suffered from gingivitis. A split mouth experimental design was used. However, patients did not receive any oral hygiene instructions during the study in order to allow the observation of the true effect of instrumentation. The outcome of a one-time treatment was assessed after 4, 14, 28, and 56 days. Gingival crevicular fluid (GCF), papilla bleeding index (PBI), plaque index (Pl-I), probing depth (PD), and relative attachment level (AL) were measured. Both treatments resulted in a statistically significant decrease of clinical signs of inflammation (PBI: p < 0.001). Probing depths decreased (p < 0.001) and a small gain of attachment of 0.11 mm +/- 0.05 mm (p < 0.001) was observed. Following treatment, a statistically significant (p < 0.001) decrease in GCF and Pl-I was observed between baseline and day 4. No statistically significant difference between the instruments' influences on the evaluated clinical parameters could be found. Thus it can be concluded indirectly that the Cavitron 2002 and the Titan-S are both useful instruments for scaling of tooth and root surfaces.

Adult↗
PubMed1994

Gingival overgrowth in cyclosporine A treated multiple sclerosis patients.

Correlations have been reported between cyclosporine A (CsA)-induced gingival overgrowth (OG) and plaque-induced gingivitis, duration of CsA therapy, and blood and tissue drug levels. We evaluated the relative importance of such factors using data from a 2-year, double-blind study of CsA therapy in multiple sclerosis (MS) patients. Ninety subjects (40 taking CsA; 50 placebo) were evaluated for plaque, calculus, gingivitis, probing depths, attachment levels, and CsA levels in blood and saliva. OG was determined by a panel of 11 calibrated examiners from standardized clinical photographs taken at the end of the study. Logistic regression was used to determine which factors were associated with occurrence of OG. Four (17%) out of 23 CsA patients with CsA trough blood levels < 400 ng/ml exhibited OG. In contrast, 10 (59%) out of 17 CsA patients with CsA trough blood levels > or = 400 ng/ml were affected with OG. Logistic regression analysis resulted in odds ratios of 0.74 (P = 0.009), 17.3 (P = 0.024) and 10.1 (P = 0.030) for the associations between OG and age, CsA trough blood levels > or = 400 ng/ml, and the interaction "color x tone," respectively. In conclusion, the incidence of CsA induced OG appears to be higher with CsA trough blood levels greater than 400 ng/ml.

Adolescent↗
PubMed1993

Comparative analysis between a modified ultrasonic tip and hand instruments on clinical parameters of periodontal disease.

The goal of this study was to determine whether an ultrasonic scaler with a modified tip is as effective as a curet in providing supportive periodontal treatment for patients, based on clinical parameters of periodontal disease. Nine patients with 10 sites exhibiting probing pocket depth > or = 3 mm were treated at 0, 90, and 180 days in a single-blind, split-mouth design for supportive periodontal treatment with either Gracey curets (GC) or an ultrasonic scaler with a modified tip (MU). Clinical parameters included plaque index, gingival index, bleeding on probing, darkfield microscopy, and elastase presence. Probing pocket depths and attachment levels were measured using an electronic probe. Measurements of clinical parameters were taken at 0, 14, 45, 90, 135, and 180 days. The results showed that treatment with MU was as effective as treatment with GC in all clinical parameters measured. Both treatment modalities were effective in reducing the elastase levels. Instrumentation time was significantly reduced with the MU (3.9 minutes vs. 5.9 minutes, P < 0.05). The MU instrument effectively reduced the microbial environment in a significantly shorter time as compared to GC.

Adult↗
PubMed1993

[Comparative probing with an electronic and a manual periodontal probe].

The goal of this study was to compare a new electronic probe (Peri-Probe) which uses a defined probing force and allows measurement of probing depth in 0.1 mm increments, with a standard manual probe. 24 sites were probed in each of 12 subjects (6 treated for periodontal disease and 6 untreated). Duplicate measurements with the electronic probe were made with the probe tip remaining in contact with gingival tissue. Similarly executed measurements using the manual probe followed during the same appointment. One week later, measurements were repeated in reversed sequence. Duplicate measurements (within appointments) resulted in measurement errors of +/- 0.18 mm for the manual probe. 98.6% of the electronic measurements and 99.3% of the manual measurements differed by < 1 mm. Replicated duplicated measurements (between appointments) resulted in measurements errors of +/- 0.86 mm for the electronic probe and +/- 0.65 mm for the manual probe. A difference of < 1 mm was found in 89.2% and 95.5% of the measurement repetitions with the electronic probe and the manual probe, respectively. The electronic probe exhibited greater variation of measurements than the manual probe. In addition, probing using the electronic instrument was more arduous than using the manual instrument, resulting in less reliable measurements.

Adult↗
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↗
PubMed1991

Different inhibitory actions of cyclosporine A and cyclosporine A-acetate on lipopolysaccharide-, interleukin 1-, 1,25 dihydroxyvitamin D3- and parathyroid hormone-stimulated calcium and lysosomal enzyme release from mouse calvaria in vitro.

The effects of cyclosporine A (CsA) and one of its immunologically inactive structural analogues, cyclosporine A acetate (CsA-A) on lipopolysaccharide (LPS)-, interleukin-1 (IL-1)-, 1,25 dihydroxyvitamin D3 (1,25 D3)- and parathyroid hormone (PTH)-stimulated bone resorption were tested in mouse calvaria cultures. The release of calcium and a lysosomal enzyme, N-acetylglycosaminidase (NAG) was determined after 3 days of culture. All bone resorbing agents potently stimulated calcium and NAG release. At therapeutic concentration levels of 0.1 and 1.0 micrograms/ml, the immunologically active CsA was significantly more potent than the inactive CsA-A against LPS- and 1,25 D3-induced calcium and NAG release. The inhibition by both cyclosporines of IL-1 and PTH stimulated calcium release was not significantly different. CsA was however more potent than CsA-A against IL-1 stimulated NAG release. PTH-stimulated NAG release was not inhibited by CsA or CsA-A. These findings suggest that both cyclosporines interfere with more than one mechanism of activation of bone resorption. The specific effect of CsA against LPS and 1,25 D3 may be related to its known inhibition of immune cell derived cytokine expression.

Acetylglucosaminidase↗
PubMed1991

An in vitro investigation on the loss of root substance in scaling with various instruments.

There are differing opinions as to the extent to which root cementum has to be removed during root surface instrumentation over and above that of the debridement of plaque and calculus. Similarly, the amount of tooth material removed by individual instruments is also unclear, but a trend towards less damaging methods of root surface debridement has evolved in recent years. The purpose of this in vitro study was to determine the amounts of root substance removed by 4 different methods of instrumentation, hand curette, ultrasonic scaler, airscaler and fine grit diamond bur. Measurement of tooth substance loss was carried out with a specially constructed measuring device at 360 sites on 90 mandibular incisors following 12 working strokes with a clinically appropriate force of application. Only a thin layer of root substance (11.6 microns) was removed by the ultrasonic scaler, compared to the much greater losses sustained with the airscaler (93.5 microns), the curette (108.9 microns) and the diamond bur (118.7 microns).

Dental Cementum↗
PubMed1991

[Fluoride excretion in schoolchildren with differing systemic fluoride care].

The aim of the present study was to collect data on urinary fluoride output in 8-16-year old students exposed to either drinking water fluoridation (DWF), or domestic salt fluoridation (DSF). Spot urine samples were collected in the canton of Basel-Stadt (DWF, n = 123), in the canton of Berne (DSF, n = 264), in the county of Davos (DSF, n = 241), and in the city of Winterthur (DSF, n = 40). Furthermore, fluoride concentrations were determined in plasma samples drawn from 33 students from Winterthur. The urinary fluoride concentrations were higher in Basel and Davos (0.62 +/- 0.35 mg/l; 0.61 +/- 0.42 mg/l) than in Berne and Winterthur (0.46 +/- 0.42 mg/l; 0.50 +/- 0.31 mg/l). A relatively high natural fluoride content (0.3 mg/l) in the drinking water explained the difference in urine fluoride concentration between students from Davos and the two other regions with domestic salt fluoridation (Berne, Winterthur). The average fluoride concentration in plasma was 12.7 +/- 3.8 ng/ml. We concluded that, in general, the supply with fluoride consumed with fluoridated domestic salt is close to the level obtained with drinking water fluoridation. However, in areas with very low systemic fluoride supplementation through the drinking water this level might not be reached with salt as the only source of systemic fluoride. Also, the data confirmed the safety of domestic salt fluoridation.

Adolescent↗
PubMed1990

[The border seal in restorations of class-V lesions with glass ionomer cement and composite (the sandwich filling)].

In 9 patients, 60 class V restorations were evaluated clinically and by scanning electron microscopy. All lesions were treated with glass-ionomer combined with composite resin. In 27 fillings (group A) the glass-ionomer lining cement was etched, whereas in 33 fillings (group B) the composite material was applied directly on the unetched glass-ionomer liner. Clinically, the retention of the fillings after one year was 100%. The margins of the fillings were checked with different explorers and found to be acceptable. Scanning electron microscopy of the margins of the fillings showed disappointing results. One week after placement of the fillings, only 16.2% (group A) and 7.4% (group B) of the cervical margins in dentin were rated perfect. After one year, even more cervical bond failures were observed. 9.7% perfect margins were found in group A, 3.2% in group B. Etching of the glass-ionomer liner had no influence on the cervical bond failure of the class V fillings.

Acid Etching, Dental↗