Clinical models that objectively evaluate interproximal plaque based on total protein concentration

AIM

To establish clinical models that accurately and objectively assess the levels of interproximal plaque (IPP) by measuring the total protein concentration.

MATERIAL AND METHODS

The multiple treatment (MTM) and single-treatment models (STM) were designed as randomized, double-blinded, crossover studies whereby IPP was collected using floss. The total protein concentration in the plaque was then measured using a fluorescence microplate assay. To demonstrate sensitivity, the levels of residual IPP were compared for two distinctly different plaque removal routines: brushing versus brushing+flossing.

RESULTS

Eighteen subjects completed the study for the MTM, while 16 participants completed the study for the STM. The results showed that both models were able to distinguish between treatments. Moreover, fundamental profiles were established that describe the mean changes in the IPP concentration over time and by treatment. Finally, a comparison between our results and a direct measure of IPP, i.e., plaque weight, demonstrated the potential of using protein as a quantitative means to assess IPP levels.

CONCLUSION

The MTM and STM provide an objective, quantitative assessment of IPP based on the total protein concentration in plaque.

Subantimicrobial dose doxycycline as an adjunct to scaling and root planing: post-treatment effects

BACKGROUND/OBJECTIVE

Subantimicrobial dose doxycycline (SDD 20 mg bid) plus scaling and root planing (SRP) significantly improved clinical attachment level (CAL) and reduced probing depth (PD) compared with placebo plus SRP in a double-blind, placebo-controlled, multicenter study of patients with adult periodontitis (AP). In a study conducted as a follow-up, the post-treatment effects of SDD were assessed in patients who completed the SRP study.

METHODS

The SRP study was a 9-month, active-treatment study and the follow-up was a 3-month, no-treatment study. In the SRP study, tooth sites in qualifying quadrants were scaled and root planed and patients were randomized to receive twice daily SDD 20 mg or placebo. In the follow-up, patients received no study drug; investigators and patients remained blinded to the previous treatment group assignments. Efficacy measures included the change in CAL and PD from baseline values determined at the start of the SRP study in tooth sites stratified by baseline PD (i.e., 0-3 mm, 4-6 mm, > or =7 mm). Safety was evaluated using adverse event data and the results of clinical laboratory tests, oral pathology examinations, and microbiological assessments.

RESULTS

Within each disease stratum, the incremental improvements in PD and CAL demonstrated in the SDD group over 9 months of active treatment were maintained through 3 additional months of no treatment. Treatment cessation did not result in an accelerated regression of periodontal health. No differences in the incidence of adverse events (including those related to infection) or laboratory or microbiological parameters were noted between the SDD group and the placebo group.

CONCLUSIONS

The administration of SDD 20 mg bid for a period of up to 9 months is not associated with rebound effects or delayed or negative after-effects for a 3-month period after cessation of therapy.

Power toothbrushes, gender, and dentin hypersensitivity

Power toothbrushes require less force for plaque removal than manual brushes. In addition, in vitro studies have indicated that brushing with low force could occlude patent dentin tubules by formation of a smear layer. Hence, lessening the force necessary to remove plaque may reduce dentin hypersensitivity. However, it was recently suggested that the use of an oscillating/rotating power toothbrush could decrease tooth sensitivity as compared to a sonic power toothbrush. Therefore, the objective of the present research was to compare the effect on dentin hypersensitivity of two different types of power brushes, the Optiva Sonicare and the Braun Oral B Ultra Plaque Remover. The null hypothesis was tested in an 8-week, randomized, parallel group, examiner-blind clinical trial. Fifty-nine subjects with a history of dentin hypersensitivity participated. Dentin hypersensitivity-associated pain was elicited using tactile and evaporative stimuli and assessed using a visual analog scale (VAS) instrument. Clinical examinations were carried out at screening and baseline and repeated after 8 weeks of twice daily use of the power brushes. Data analysis was performed on VAS scores obtained at the final visit following adjustment for group differences at baseline. A 35% to 40% reduction in pain as compared to baseline was observed in both treatment groups. Treatment-related differences were not statistically significant. A gender-related effect on dentin hypersensitivity was observed using the tactile stimulus and may merit further investigation.

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.

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.

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.

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.

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.

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.

Factors affecting cyclosporine-induced gingival overgrowth in pediatric renal transplant recipients

The purpose of this research was to study the occurrence of gingival overgrowth (GO) in children after kidney transplantation and to investigate the relationship of GO to medical and dental parameters. Forty-nine kidney transplant patients taking the immunosuppressive drug cyclosporine A (CsA) were evaluated for plaque (PI), calculus (CI), gingival inflammation (GI), probing depth (PD), width of keratinized gingiva (GW), and gingival overgrowth (GO). Blood trough levels and oral dosages of CsA were obtained from medical charts on the day of examination. Most (77.5%) subjects exhibited GO, suggesting that GO is a frequent problem in children and adolescents ingesting CsA. GI, PD, and GW were found to be statistically significantly greater in subjects with GO than in those without GO. CsA dose/day was not significantly different between subjects with GO and those without GO. CsA dose/kg body weight and blood trough levels of CsA were significantly higher in subjects without GO, but the average length of time subjects without GO had been ingesting CsA was only 1.3 months, compared with an average 3.5 years for subjects with GO. The results indicate that in young subjects, duration of CsA ingestion may be the most critical factor related to eventual GO development.

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.

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.

Osseointegrated dental implants as alternative therapy to bridge construction or orthodontics in young patients: seven years of clinical experience

Young patients often require fixed bridgework or orthodontic therapy in cases of traumatic tooth loss or congenitally missing teeth. Dental implants represent an alternative to the more conventional treatment methods. We report positive experience over a seven-year period with 42 titanium Ha-Ti implants in 34 patients aged 9 to 18 years. Fourteen implants were placed into prepared tooth sockets immediately after traumatic luxation of anterior teeth in 12 patients aged 9 to 18 years (median age 16). An additional 22 patients (median age 15.5, range 11 to 18) also received implants (N = 28), but these were placed only after healing of extraction sites, or as substitutes for congenitally missing teeth. Implants remained in situ for an average of 7.7 months before loading. During the healing period, three implants were lost due to additional trauma and one became infected. The 38 remaining implants osseointegrated and since have been loaded for five to 79 months in successful function. There was no difference between immediate and delayed implants in clinical success. These experiences demonstrate that appropriate, versatile, osseointegrated implants can provide a successful treatment method for young patients, without damaging adjacent teeth.

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.

Sugar substitutes in dental caries prevention. Significance of sorbitol and xylitol

To date, effective caries prevention largely relies on the regular use of fluoride and oral hygiene. The potential efficacy of basing caries prevention on nutritional modifications has been suggested a long time ago. Subsequently, a great number of laboratory, animal and clinical investigations have convincingly demonstrated that partial substitution of sugar by noncariogenic sweeteners offers considerable benefits for dental health. This article reviews scientific information on sorbitol and xylitol, two caloric sugar substitutes that have been extensively studied with regard to their noncariogenic properties.

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).

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.

The effectiveness of root debridement in open flap procedures by means of a comparison between hand instruments and diamond burs. A SEM study

The goal of the present in vivo study was to evaluate human roots by means of scanning electron microscopy (SEM), after treating the root surfaces either with conventional hand instruments or with newly developed diamond burs. Peculiar root anatomy often makes perfect instrumentation with hand instruments difficult or impossible. On 20 teeth destined for extraction because of severe periodontitis, the root surfaces were exposed by mucoperiosteal flap procedures. Ten roots were then planed using fine curettes, and 10 were instrumented using diamond burs. Following extraction, the root surfaces were stained and photographed. Stained areas were examined by SEM. On the 20 test teeth, 79 surfaces were evaluated. From these, 381 stained zones were checked by SEM for the presence of bacteria. A total of 216 stained areas from teeth treated by hand instruments was evaluated; 15 of these (6.9%) contained bacteria. Of roots treated by diamond burs, 165 stained areas were evaluated; 9 (5.5%) exhibited bacteria. Thus, both methods resulted in root surfaces that were essentially bacteria-free.

The effect on early plaque formation, gingivitis and salivary bacterial counts of mouthwashes containing hexetidine/zinc, aminefluoride/tin or chlorhexidine

This study was designed to investigate the effectiveness of mouthwashes containing hexetidine/zinc (HZA) or tin (ASF) in inhibiting plaque formation and gingivitis in humans. 24 dental students and assistants participated in the study (latin square design) with 7-day test periods. They rinsed twice daily for 1 min with one of the following formulations: HZA = 750 ppm hexetidine/750 ppm zinc acetate, ASF = 100 ppm aminefluorid/310 ppm stannous fluoride, CHX = 0.1% chlorhexidine and M = negative control. Plaque accumulation was determined planimetrically and gravimetrically. Gingivitis was evaluated with the papillary bleeding index. Total colony forming units and S. mutans counts were estimated from saliva samples. The results showed that HZA and CHX almost completely inhibited plaque accumulation and gingivitis. ASF was less effective than HZA and CHX but still reduced plaque significantly compared to the negative control. Furthermore, CHX reduced salivary S. mutans counts.