The Future of Web-based Clinical Research in Dentistry

Clinical research is a growing industry in dentistry, requiring more efficient methods for research conduct. The Internet provides an opportunity for investigators to expand, enhance, and potentially redefine the way they conduct clinical research. A prime area for improved research is in clinical trials processes, due to their current high cost and inefficiencies. The Web offers the advantages of both centralization of information and coordination of multiple clinical trials processes. The result is improvements for the investigator sites, the sponsor, and subject safety. Observational studies also provide the opportunity for investigators to collect greater amounts of information in a more realistic dental environment. The Internet offers investigators the opportunity to collect outcomes information from sources worldwide, and more efficiently, accurately, and quickly, providing new valuable research answers. The tremendous explosion of genetic and gene therapy research will substantially increase the need for research methods that can manage the vast amount of complex new data, depending on the Internet to manage these research needs. The Internet holds promise for improving dental clinical research through its gains in efficiency, accuracy, and safety.

Paradigm shifts in clinical trials enabled by information technology

The use of the world wide web for clinical trials changes the processes of performing clinical research in several fundamental ways. Greatly improved security, monitoring capability, and accuracy and timeliness of study conduct can be achieved while lowering cost. Data quality is enhanced while co-ordinating centre effort is reduced. The web provides a natural environment for linking the various components of clinical research, leading to new levels of simplicity and efficiency. It also enhances opportunities for recruitment of study investigators and patients. Other information technology tools and databases can be used to assist in this regard as well. Web-based trials change the relationship of the investigator site to the study and the site to the co-ordinating centre. Different roles and responsibilities lead to simplified processes and more and higher quality data. Many standard co-ordinating centre activities, such as randomization, protocol implementation and amending, document tracking, adverse event reporting, site monitoring, report generation and data analysis are all fundamentally changed in a web-based trial. Opportunities are enhanced to identify potential investigators and support their successful study conduct. As the role of investigator sites is changed in web-based research, more primary care medical providers can be attracted to research, providing more typical patients to studies than those sometimes available through more traditional research sites, especially those at academic study sites. Other activities can now be co-ordinated electronically with the advent of the web. The Institutional Review Board (IRB) can use online tools to control investigator participation, resulting in improved study efficiency and patient safety. A web-based research pharmacy provides tremendous efficiencies in managing and distributing study medications. Financial payments to the sites can be performed and recorded electronically, or even administered based on timeliness and quality of the data. Our early experience with web-based trials indicates that there can be tremendous gains in study efficiency and accuracy by restructuring processes, roles and responsibilities through a comprehensive centralized, web-based trial. The future appears bright for web-based clinical trials.

Rationale and design of the International Verapamil SR/Trandolapril Study (INVEST): an Internet-based randomized trial in coronary artery disease patients with hypertension

OBJECTIVES

The primary objective of the International Verapamil SR/Trandolapril Study (INVEST) is to compare the risk for adverse outcomes (all-cause mortality, nonfatal myocardial infarction [MI] or nonfatal stroke) in hypertensive patients with coronary artery disease (CAD) treated with either a calcium antagonist-based or a noncalcium antagonist-based strategy.

BACKGROUND

Treatment recommendations for hypertension include initial therapy with a diuretic or beta-adrenergic blocking agent, for which reductions in morbidity and mortality are documented from randomized trials but are less than expected from epidemiologic data. For this reason, recent attention has focused on calcium antagonists or angiotensin-converting enzyme inhibitors. While these agents reduce blood pressure, outcome data from large randomized trials are lacking, but some case-control data, dominated by short-acting dihydropyridines, suggest an increased risk of cardiovascular events. These studies had methodologic limitations and did not differentiate among calcium antagonist types and formulations. Several studies differentiating among calcium antagonist types and an overview of published randomized trials show no increased risk with verapamil and suggestion for benefit in CAD patients.

METHODS

A total of 27,000 CAD patients with hypertension will be randomized at 1,500 primary care sites to receive either a calcium antagonist-based (verapamil) or beta-blocker/diuretic-based (atenolol/hydrochlorothiazide) antihypertensive care strategy. The study uses a novel, electronic "paper-less" system for direct on-screen data entry, randomization and drug distribution from a mail pharmacy linked to the coordination center via the Internet.

RESULTS

Contract negotiations with the United States and international sites are ongoing. Patients being enrolled are predominantly elderly (72% aged 60 years or older) men (54%), with either an abnormal coronary angiogram or prior MI (71%). In addition to hypertension, CAD and elderly age, most patients (89%) have one or more associated conditions (diabetes, dyslipidemia, smoking, cerebral or peripheral vascular disease, etc.) contributing to increased risk for adverse outcome. While 26% have diabetes, most of these are noninsulin dependent. Using the protocol strategies, target blood pressures (according to JNC VI) have been reached in 58% at the fourth visit, and as expected most (89%) are requiring multiple antihypertensive drugs.

CONCLUSION

The design and baseline characteristics of the initial patients recruited for a prospective, randomized, international, multicenter study comparing two therapeutic strategies to control hypertension in CAD patients are described.

Otologic and audiologic status of Russian children with cleft lip and palate

OBJECTIVE

In this study, researchers evaluated the otologic and audiologic status of 112 children with repaired cleft lip and palate who had received primary palatal repair by means of Frolova palatoplasty, a surgical technique developed by Dr. Larisa Y. Frolova, founder and director of the National Pediatric Center for Congenital Maxillofacial Pathology, Moscow, Russia.

DESIGN

Results of hearing thresholds and tympanograms for these Russian children were compared with data previously reported from a group of 48 children and adults with repaired cleft lip and palate at the University of Florida Craniofacial Center, Gainesville, Florida.

RESULTS

There were no substantial differences in hearing thresholds between the two groups, which was surprising in view of the vast differences between middle ear management techniques used in Russia and the United States.

CONCLUSIONS

Considering these findings and the growing body of literature favoring a more conservative approach to the management of middle ear effusion in infants with cleft lip and palate, a reexamination of otologic strategies in the United States seems advisable.

Velopharyngeal function for speech after the Frolova primary palatoplasty technique

OBJECTIVE

This study was undertaken by several members of the University of Florida Craniofacial Center to assess the results of palatoplasty performed by the method devised by Larisa Y. Frolova, M.D. in 1971.

DESIGN

The assessment was based on evaluation of each subject's speech and velopharyngeal function through perceptual measures, nasometry, and video-nasendoscopy.

SETTING

The study took place at the National Pediatric Center for Congenital Maxillofacial Pathology, Moscow, Russia, under the auspices and with the cooperation of Dr. Frolova, director of the program.

SUBJECTS

One hundred twelve children (40 girls and 72 boys; age range, 4 to 10 years; mean age, 7.5 years) with repaired cleft palate who had undergone palatoplasty 2 to 4 years earlier and had no secondary surgery were randomly selected from the center's clinical files by the staff. Subjects with known conditions that could jeopardize normal speech development were excluded.

METHODS

Each subject was assessed for speech and velopharyngeal function with a battery of perceptual measures and videonasendoscopy.

RESULTS

The percentage of subjects judged to have normal resonance was 55.5%. An additional 9.5% of the subjects judged to be hyponasal increased the rate of nonhypernasal outcome to 64%.

CONCLUSIONS

The Furlow double-Z palatoplasty has had an increasing rate of success (up to 87%), whereas the Frolova technique has a success rate of only 55% to 65%.

Effects of intermittent transdermal nitroglycerin on occurrence of ischemia after patch removal: results of the second transdermal intermittent dosing evaluation study (TIDES-II)

OBJECTIVES

We sought to evaluate the effects of intermittent transdermal nitroglycerin (TD-NTG) on the occurrence of ischemia during patch-off hours in patients with stable angina pectoris receiving a beta-adrenergic blocking agent or calcium antagonist, or both.

BACKGROUND

The current recommendations for the use of intermittent TD-NTG may be associated with the occurrence of rebound ischemia.

METHODS

This was a multicenter, randomized, double-blind, placebo-controlled, crossover trial with three study periods. Tolerability to TD-NTG was assessed in Period I. Seventy-two patients were assigned to receive either double-blind transdermal placebo or maximally tolerated TD-NTG for 2 weeks (Period II) and were then crossed over to the alternative treatment for another 2 weeks (Period III). The patients were instructed to apply medication daily at 8 AM, to remove it at 10 PM and to note symptoms and sublingual nitroglycerin (SL-NTG) use in a diary. The occurrence of ischemia was assessed from patient-perceived angina, symptom-limited exercise treadmill test (ETT) and 48-h ambulatory electrocardiographic (AECG) monitoring.

RESULTS

Transdermal NTG (0.2 to 0.4 mg/h) significantly reduced the magnitude of ST segment depression at angina onset during ETT compared with placebo. Total angina frequency was not significantly different between TD-NTG (mean [+/-SD] 3.2 +/- 4.2) and placebo (3.3 +/- 5.2). During patch-off hours, angina frequency increased with TD-NTG (1.1 +/- 2.1) compared with placebo (0.7 +/- 1.6) (p = 0.03). Similar trends for an increase in ischemia after TD-NTG were also observed from AECG analyses. Specifically, ischemia frequency tended to be lower during patch-off hours for placebo than with TD-NTG (0.05 +/- 0.09 vs. 0.08 +/- 0.20 episodes/h, respectively, p = 0.08), even though frequency of ischemia tended to be higher during patch-on hours for placebo than with TD-NTG (0.12 +/- 0.19 vs. 0.07 +/- 0.15 episodes/h, respectively, p = 0.11). During placebo, ischemia frequency decreased 58% (patch-on to patch-off, p = 0.01) compared with a 14% increase with TD-NTG. These changes attenuate the usual circadian variation in ischemia.

CONCLUSIONS

An increase in ischemia frequency during patch-off hours after use of intermittent TD-NTG was perceived by patients, and this subjective finding was supported by a corresponding trend for AECG ischemia to increase during these same hours.

Fimbrial-mediated colonization of murine teeth by Actinomyces naeslundii

Groups of mice fed diets high in sucrose or glucose were orally inoculated with 10(10), 10(9) or 10(8) colony-forming units of one of the following Actinomyces naeslundii strains possessing the type 1 (T1+) and/or the type 2 (T2+) fimbriae: T14VJ1 (T1+, T2+), 5519 (T1+), 5951 (T2+), and 147 (non-fimbriated). Ninety-six hours after inoculation their upper jaws were cultured to look at the implantation of each of these strains on the teeth. In mice fed a sucrose diet, regardless of the presence or absence of fimbriae, each bacterial strain colonized 100% of the mice at the highest inoculation doses of the infecting organism. But at a dose of 10(8), T14V-J1 was the only strain which colonized 100% (12/12) of the mice, 5519 colonized 10/11, 5951 colonized 9/11 and 147 colonized 7/11. These differences were not statistically significant. When mice were fed a high-glucose diet, 100% infection was achieved with strains T14V-J1, 5519 and 5951 only at the highest dose of 10(10) colony-forming units. Strain 147 colonized in 8/9 of the mice at that dosage. At lower dosages, no bacterial strain implanted in 100% of the mice. In the glucose experiment at a dose of 10(8), strains expressing the T1 fimbriae implanted significantly better than strains without the T1 fimbriae. At a dose of 10(9) colony-forming units, the parent strain T14V-J1 implanted significantly better than strains without the T1 fimbriae. Similarly, strain 5519 (T1+) implanted significantly better than 5951 and implanted better than 147, although the difference was not significant. These results suggest that while the presence of the T1 and T2 fimbriae may confer some advantage in the establishment of these organisms in vivo, even the strains without fimbriae were able to colonize. Strains T14VJ1 and 5519 were found to bind well to hydroxyapatite treated with mouse saliva, while strains 5951 and 147 did not. Only T2 fimbriated strains T14V-J1 and 5951 exhibited a lactose-reversible coaggreation with indigenous strains of enterococci that may contribute to the elevated levels of colonization of strain 5951 in vivo.

Arcuate Transverse Keratotomy for Astigmatism Followed by Subsequent Radial or Transverse Keratotomy

BACKGROUND

We studied the safety and efficacy of arcuate transverse keratotomy performed for the primary correction of naturally occurring corneal astigmatism.

METHODS

A multicenter, prospective evaluation of one-stage arcuate transverse keratotomy was conducted in 160 eyes with 1.00 to 6.00 diopters (D) of naturally occurring astigmatism. Vector analysis was used. After 1 month, those eyes that needed further refractive surgery received radial keratotomy for myopia and second-stage arcuate transverse keratotomy for residual astigmatism.

RESULTS

Mean preoperative refractive cylinder was 2.80 D. At 1 month, the vector-corrected change was 2.30 D. Eighty-eight (61%) eyes had at least 1.00 D of residual refractive cylinder and 24 (17%) had at least 2.00 D. Eyes undergoing a second surgery averaged 1.60 D of vector-corrected effect, for a total effect of 2.90 D from both surgeries, indicating the astigmatic refractive effects were not additive. Eyes that had radial keratotomy alone as the second surgery demonstrated a similar change in refractive cylinder as eyes that had both radial and transverse keratotomies. Two eyes lost two lines of spectacle-corrected visual acuity, 29 eyes lost one line, 84 showed no change, and 26 eyes improved one line.

CONCLUSION

Arcuate transverse keratotomy reduced refractive astigmatism. Both overcorrection and undercorrection were common. Complications were infrequent but occasionally caused significant irregular astigmatism. Arcuate transverse keratotomy appears to be a safe procedure with few complications.

Ten-year refractive and visual results of radial keratotomy

PURPOSE

The authors evaluated the 10-year refractive and visual acuity results of a cohort of patients who underwent radial keratotomy (RK).

METHODS

A prospective cohort study was begun in 1980 of 198 consecutive myopic eyes of patients who were to undergo RK surgery. Patients were at least 18 years of age with myopia between 1.75 and 10 diopters. All patients signed consent forms. Refraction, uncorrected visual acuity (UVA), and best corrected visual acuity (BCVA) were the main outcomes evaluated at 10 years.

RESULTS

Mean refraction at 10 years was -0.12 D, compared with -0.43 D at 5 years. Fifty-seven percent of eyes had UVA of at least 20/40 at 10 years, compared with 55% at 5 years. Improvement in UVA between 5 and 10 years occurred most frequently in eyes with most preoperative myopia and most surgery. Eighty-five percent of eyes had BCVA of at least 20/25 at 10 years, compared with 81% at 5 years. Women had significantly less myopia then men before surgery (P < 0.01), yet had similar UVA and worse BCVA. At 10 years, women had similar refraction but worse UVA and BCVA than men.

CONCLUSIONS

Radial keratotomy was shown to be effective 10 years later. Some refractive and acuity changes occurred between 5 and 10 years follow-up, but these were mainly normal physiologic changes that occur with aging. Women had poorer vision than men before RK surgery and less beneficial results after surgery.

A longitudinal evaluation of dipyridamole drug use in an ambulatory elderly population

STUDY OBJECTIVE

To determine the pattern of dipyridamole use over the past 14 years.

DESIGN

A longitudinal health screening program of ambulatory elderly participants was used to study changes in dipyridamole drug use. Participants included all subjects screened in the Florida Geriatric Research Program since 1978. The main outcome measure in this study was self-reported dipyridamole use at every visit to the program since August 1, 1978.

RESULTS

A total of 3.6% of men (mean age, 82.6 years) and 3.4% of women (mean age, 80.8 years) reported the use of dipyridamole in the 1991-1992 period. The prevalence of dipyridamole use ranged from a low of 1.6% in 1978-1979 to a high of 7.3% in 1986-1987. There was a significant increase in the use of this drug from 1978-1979 to 1991-1992 (p < 0.038). Over the 14-year period of study, the percent of subjects using dipyridamole concurrently with coumarin anticoagulants ranged from a low of 5.8% to a high of 17.9%.

CONCLUSIONS

The level of dipyridamole use in this elderly population has increased since 1978-1979. The only FDA indication for this drug is in combination with coumarin anticoagulants to prevent postoperative thromboembolic complications of cardiac valve replacement. Less than 20% of patients in this study used the drug in combination with coumarin anticoagulants. Educational programs are needed to improve the prescribing of dipyridamole.

Astigmatism reduction clinical trial: a multicenter prospective evaluation of the predictability of arcuate keratotomy. Evaluation of surgical nomogram predictability. ARC-T Study Group

OBJECTIVE

To determine the accuracy of the Lindstrom surgical nomogram for astigmatism.

DESIGN

A prospective multicenter study.

PATIENTS

One hundred sixty eyes of 95 patients underwent astigmatic keratotomy in eight centers by nine surgeons. Inclusion criteria for the study included age of at least 18 years with 1 to 6 diopters (D) of naturally occurring corneal astigmatism and less than 1 D of lenticular astigmatism.

INTERVENTIONS

A standardized astigmatic keratotomy surgical technique was performed on each eye. Surgical measurements were determined using the Lindstrom surgical nomogram for astigmatism.

MAIN OUTCOME MEASURE

The Holladay, Cravy, Koch vector analysis method was used to determine the change in refractive cylinder results. Refractive changes also are presented without vector analysis merely using the absolute change in refractive cylinder and axis.

RESULTS

Multiple regression analysis was used to develop a mathematical model determining the factors predictive of the change in refractive cylinder. The significant predictors for the amount of astigmatic correction achieved were, in order of decreasing importance, the following: number of incisions (R2 = 30%), incision length (R2 = 16%), age (R2 = 8%), and gender (R2 = 2%).

CONCLUSIONS

Astigmatism is a two-dimensional measurement of both quantity and direction that is most appropriately analyzed with vector analysis. The original Lindstrom surgical nomogram for arcuate keratotomy used in this study is still quite useful although it tended to underpredict results for many patients, especially those having two incisional surgeries. Some older subjects having minimal surgery achieved greater correction than predicted by the original nomogram. The most important factors predictive of greater astigmatic keratotomy surgical effect are incision number, incision length, older age, and male gender.

Treatment of subjects with refractory periodontal disease

The aim of the present study was to evaluate the effect of non-surgical periodontal therapy with the adjunct of a selected antibiotic in subjects diagnosed with refractory periodontal disease. 21 subjects were selected for the study; all had a history of periodontal surgery, tetracycline therapy, and regular maintenance by a periodontist. When disease activity was detected, a bacterial sample was taken and a whole plaque susceptibility test was performed. Before the outcome of the susceptibility test the subjects were assigned to either antibiotic or placebo therapy. All subjects received scaling and rootplaning prior to antibiotic or placebo therapy. Based on the susceptibility test, subjects in the antibiotic group were treated either with Augmentin or clindamycin. The results demonstrated that in subjects with refractory periodontal disease there was no significant difference (N.S.) in the proportion of sites losing attachment before and after treatment (11.3% and 12.4%, respectively) over a 2-year post therapy observation period. However, the proportion of sites showing gain of attachment increased from 0.9% before therapy to 5.1% (p = 0.029) following selective antibiotic therapy when combined with scaling and rootplaning. The remainder of sites showed no change between pre- and post-therapy monitoring periods. The progression of attachment loss in the active sites could not be completely stopped over the entire 2-year period. After 12-15 months following therapy, there was a tendency towards new loss of attachment and an increase of pocket depth. However, all 4 subjects treated with placebo drug demonstrated continuous deterioration and had to be retreated. Although the proportion of sites losing attachment decreased from 5.1% to 2.3% (N.S.), the proportion of sites gaining attachment also decreased from 2.0% to 1.0% (N.S.). The results suggest that scaling and rootplaning together with selected antibiotic therapy repeated every 12-15 months may be beneficial for these subjects although it may not completely stop progressive attachment loss.

Effects of treatment on outcome in mildly symptomatic patients with ischemia during daily life. The Atenolol Silent Ischemia Study (ASIST)

BACKGROUND

Detection of asymptomatic ischemia in patients with coronary artery disease has been associated with increased risk for adverse outcome, but treatment of patients with asymptomatic ischemia remains controversial. Accordingly, the purpose of this study was to determine if treatment reduces adverse outcome in patients with daily life ischemia.

METHODS AND RESULTS

A multicenter, randomized, double-blind, placebo-controlled study of asymptomatic or minimally symptomatic outpatients with daily life silent ischemia due to coronary artery disease was conducted. The primary outcome measure was event-free survival at 1 year by Kaplan-Meier analysis. Events were death, resuscitated ventricular tachycardia/fibrillation, myocardial infarction, hospitalization for unstable angina, aggravation of angina, or revascularization. The secondary outcome was ischemia during ambulatory ECG monitoring at 4 weeks. Three hundred six outpatients with mild or no angina (Canadian Cardiovascular Society class I or II), abnormal exercise tests, and ischemia on ambulatory monitoring were randomized to receive either atenolol (100 mg/d) or placebo. After 4 weeks of treatment, the number (mean +/- SD, 3.6 +/- 4.2 versus 1.7 +/- 4.6 episodes, P < .001) and average duration (30 +/- 3.3 versus 16.4 +/- 6.7 minutes, P < .001) of ischemic episodes per 48 hours of ambulatory monitoring decreased in atenolol- compared with placebo-assigned patients (4.4 +/- 4.6 to 3.1 +/- 6.0 episodes and 36.6 +/- 4.1 to 30 +/- 5.5 minutes). Event-free survival improved in atenolol-treated patients (P < .0066), who had an increased time to onset of first adverse event (120 versus 79 days) and fewer total first events compared with placebo (relative risk, 0.44; 95% confidence intervals, 0.26 to 0.75; P = .001). There was a nonsignificant trend for fewer serious events (death, resuscitation from ventricular tachycardia/fibrillation, nonfatal myocardial infarction, or hospitalization for unstable angina) in atenolol-treated patients (relative risk, 0.55; 95% confidence intervals, 0.22 to 1.33; P = .175). The most powerful univariate and multivariate correlate of event-free survival was absence of ischemia on ambulatory monitoring at 4 weeks. Side effects were mild and generally similar comparing atenolol- and placebo-treated patients, although bradycardia was more frequent with atenolol.

CONCLUSIONS

Atenolol treatment reduced daily life ischemia and was associated with reduced risk for adverse outcome in asymptomatic and mildly symptomatic patients compared with placebo.

Characteristics of a contemporary population with angina pectoris. TIDES Investigators

To characterize a contemporary, nonhospitalized population with angina pectoris, data were obtained from a geographically diverse cohort of 5,125 outpatients with chronic stable angina cared for by 1,266 primary care physicians between September and November of 1990. Diagnosis was based on history supported by evidence for coronary artery disease (coronary angiography, old myocardial infarction, or an abnormal stress test, either alone or in combination). The mean age of the patients was 69 years and 53% were women. Seventy percent had > 1 associated illness and 64% took > 1 cardiovascular drug. Median angina frequency was approximately 2 episodes/week and increased angina frequency (p < 0.0001) was associated with decreased overall feeling of well-being. Although effort angina was present in 90% of patients, 47% also had rest angina and 35% had mental stress-evoked angina. Female gender (relative risk [RR] 1.09; 95% confidence interval [CI] 1.02 to 1.16), concomitant illness (RR 1.17; CI 1.09 to 1.25), and pharmacotherapy (RR 1.14; CI 1.07 to 1.22) were associated with excess risk for rest angina. Younger age (RR 1.30; CI 1.20 to 1.41), female gender (RR 1.16; CI 1.07 to 1.26), concomitant illness (RR 1.13; CI 1.03 to 1.24), and pharmacotherapy (RR 1.28; CI 1.15 to 1.93) were associated with excess risk for mental stress angina. These data suggest that contemporary outpatients with angina are frequently women and elderly patients with high rates of associated illness, rest, and mental stress-related angina.

Results from a three-year caries clinical trial comparing NaF and SMFP fluoride formulations

A three-year, double blind, randomised clinical trial was conducted in Polk County, Florida from 1983-1987. The objective was to compare the effect of four dose levels of sodium monofluorophosphate (SMFP) and a single dose level of sodium fluoride (NaF) on DMFS, DMFT, and DFS Interproximal indices. A total of 8,027 children were examined clinically and radiographically at baseline, and 5,474 children completed the three-year study, which included daily supervised brushing at school. No differences existed at baseline between the five study cells on age or gender distribution, or on any of the dental indices. Results indicated that the 2000 ppm F NaF group had significantly smaller DMFS increment than the 2000 ppm F SMFP group p < 0.005. The 2000 ppm F NaF group demonstrated an 18 per cent (26 per cent for children > 10 years at baseline) reduction in DMFS over the 1500 ppm F SMFP group, the 2500 ppm F group a 15 per cent (19 per cent) reduction, and the 2000 ppm F SMFP a 5 per cent (9 per cent) reduction. Results are strongest in children at greatest risk--older children with previous caries. This study concludes that the anticaries efficacy of SMFP dentifrices rises with increasing fluoride, and that the anticaries efficacy of a 2000 ppm NaF dentifrice is superior to that of a 2000 ppm F SMFP dentifrice, p < 0.005).

Modeling the relationship between clinical, microbiologic, and immunologic parameters and alveolar bone levels in an elderly population

A cross-sectional periodontal study of 74 subjects aged 65 to 75 years was performed. Clinical data were collected and related to microbiological and immunological data. A statistical model (step-wise multiple regression) of factors related to bone loss was created initially using clinical data only; then by adding either the microbiologic or immunologic data; and then by using clinical, microbiologic, and immunologic data together. When only clinical data were considered, three factors were found to have significant positive correlations with bone loss. Tooth mobility accounted for 17% of the variability in the alveolar bone level measurements, probing depth for 12%(r2), and plaque index for 3%, for a total of 32% of the variability explained by these clinical factors. Tooth mobility and probing depth were clinical factors which remained significant in the model when the microbiological data were also considered. As percentages of the total cultivable microbiota, E. corrodens (r2 = 14%) and black-pigmenting Prevotella intermedia (r2 = 4%) correlated positively with alveolar bone loss. The addition of the microbiologic data only increased the r2 to 33%. When immunological data were considered with the clinical data, pocket depth and tooth mobility were the clinical parameters which remained in the model. IgG antibody levels to P. gingivalis W83 and/or 381 (r2 = 24%) A. actinomycetemcomitans 627 (r2 = 2%) were the significant immunologic measures having a positive correlation with bone loss. Anti-F. nucleatum levels had a significant negative correlation. A total of 50% of the variability in alveolar bone level was accounted for in the model by the addition of specific serum antibody levels to subgingival plaque microorganisms. When clinical, microbiological, and immunological measurements were all considered together, antibody to P. gingivalis W83 and/or 381 (r2 = 42%), percentage of B-lymphocytes (r2 = 3%), probing depth (r2 = 4%), anti-E. corrodens levels (r2 = 2%), and anti-P. gingivalis 33277 levels (r2 = 4%) all had significant positive correlation with loss of alveolar bone. The number of enteric bacteria, anti-F. nucleatum levels, and anti-P. intermedia levels each had a significant negative correlation with alveolar bone heights. The r2 for this model was 75%. These results indicated that antibody levels to subgingival plaque microorganisms and tooth mobility were the best predictors of bone loss in the elderly patients tested in this study.

Benzodiazepine use in an ambulatory elderly population: a 14-year overview

A survey on use of benzodiazepines was conducted among participants in the Florida Geriatric Research Program. In 1978-79, benzodiazepine use was reported by 14.4% of 1448 women and 9.7% of 855 men; in 1984-85, by 12.0% of 1429 women and 5.9% of 784 men; and in 1991-92, by 13.4% of 1124 women and 6.6% of 497 men. The changes were not significant. During this period the mean ages of the women increased from 74.6 to 78.1 years and the men from 75.0 to 80.2 years. Chlordiazepoxide, diazepam, and flurazepam accounted for 98.1% of all benzodiazepines used in 1978-79 and for 35.5% in 1991-92, when alprazolam, lorazepam, and temazepam accounted for 47.1% of benzodiazepines used.

Five-year corneal graft survival. A large, single-center patient cohort

OBJECTIVE

To determine the survival rates and causes of secondary graft failure in a large, consecutive series of penetrating keratoplasties.

DESIGN

All eyes undergoing penetrating keratoplasty at a single center were evaluated for factors relating to penetrating keratoplasty preoperatively, surgically, and postoperatively at 1, 3, 6, 9, 12, 18, and 24 months and then at yearly intervals. Since 1986, data analysis has been prospective.

SETTING

A large, private practice, tertiary center for corneal disorders and surgery.

PATIENTS

A consecutive series of 1819 penetrating keratoplasties performed from August 1982 through August 1990; 13 eyes with primary graft failure were excluded.

MAIN OUTCOME MEASURE

Graft failure and causes of failure. Follow-up ranged from 1 to 96 months, with a mean of 26.6 months.

RESULTS

Pseudophakic bullous keratopathy was the most common diagnosis necessitating keratoplasty (38.6%). Secondary failures occurred 111 times (6.1%). The 2- and 5-year survival rates for all grafts in the study were 95% and 91%, respectively. While endothelial failure as a result of immunologic allograft reactions was the most common cause of graft failure (27%), problems with the external surface of the graft caused nearly as many failures (25%). The risk of failure from surface-related problems was highest at 3 months after surgery. There were significantly decreased survival rates for grafts in eyes with regrafts (P < .0001), in eyes left aphakic at keratoplasty (P < .0001), and in eyes with deep stromal vascularization (P < .0001).

CONCLUSION

Penetrating keratoplasty is a successful form of transplantation, and survival rates are gradually increasing. The risk of graft failure appears highest within the first year after transplantation.

Change detection on longitudinal data in periodontal research

Longitudinal data of attachment level (AL) or the alveolar bone level are often used to assess the progression of periodontal disease. This paper tries to identify the most efficient method to detect the changes of AL in a general periodontal research environment; that is, a sequential decision based on multiple sites. Several existing methods suggested in the periodontal research literature such as the tolerance, running median, cusum, and regression methods as well as change-point detection methods in the statistical literature are examined. It is found that the regression method is most convenient among the several methods that are equally effective in change detection. Formulae, tables and their usage are discussed in detail.

Evaluation of reliability and reproducibility of dental indices

Evaluation of periodontal therapy involves the use of several oral indices to describe the health status of hard and soft tissues. It was the objective of the present study to evaluate the reliability and reproducibility of some of these indices. A calibration and standardization session was designed to calibrate 10 examiners and a "gold standard" (an experienced examiner) in evaluating the following indices: the Volpe-Manhold calculus index (VM), the Lobene stain index (SI), a non-invasive modification of the Löe-Silness gingival index (GI), the papillary bleeding score (PBS) of Loesche, and the plaque index (PI) of Quigley-Hein as modified by Turesky. For each index, the average intraclass correlation was calculated between two subject visits. The highest intraclass correlation, 0.94, was found for PBS. The intraclass correlation for PI was 0.70 and for VM, 0.65. The lowest intraclass correlations were for stain, 0.47, and GI, 0.25. Intra-subject correlations between the 2 visits were good for all indices, but were best for PBS, followed by VM. PBS seems to be the most reliable index (both intra- and inter-examiner) for measuring the oral health status and is therefore recommended for use in clinical studies.

Nocturia: a risk factor for falls in the elderly

OBJECTIVE

To determine if nocturia is a risk factor for reported falls and bone fractures in older persons.

DESIGN

Cross-sectional study comparing falls in men and women with and without nocturia.

SETTING

Longitudinal health screening program of ambulatory elderly participants.

PARTICIPANTS

Participants included 988 (65.5%) women and 520 (34.5%) men who had completed their tenth annual visit to the program.

MAIN OUTCOME MEASURES

Reported falls in the past year and reported bone fractures in the past 5 years.

RESULTS

Participants who reported nocturia at least twice during the night were at significantly greater risk to report falls (Odds Ratio = 1.84; 95% CI = 1.05-3.22), and the risk increased in subjects reporting more than three nocturia events (Odds Ratio = 2.15; 95% CI = 1.04-4.44). The significant increase in falls reported by nocturia participants did not result in an increase in reported bone fractures in the past 5 years (P < 0.4360).

CONCLUSIONS

Nocturia is an important risk factor for falls in ambulatory elderly persons. Preventive measures should be taken to decrease nocturia events and to decrease the risk of falling during these nocturia events.

Reproducibility of an electronic probe in relative attachment level measurements

4 probing designs have been employed to investigate the reproducibility of the Florida Probe. 3 groups (each composed of 10 subjects) were selected for the study: healthy adults, gingivitis subjects, and periodontitis subjects. The 4 probing designs were as follows: (a) the probe tip was left in the sulcus between successive probings; (b) the probe tip was removed from the gingival margin between probings but the next probing followed immediately; (c) successive whole-mouth probings were interrupted by a 5-min interval and a mouthrinse; (d) there was a 4-week interval between each probing. 3 measurements were taken for each design. The main purpose of this study was to identify variance components in the attachment level variation. The maximum probing error standard deviation was found to be around 0.3 mm, which is considerably smaller than that found in most previous studies. The errors associated with the periodontal condition and probing effect were also estimated. The variance components obtained here can be used for determining the sample size in controlled clinical studies.

Correlates of constipation in an ambulatory elderly population

Constipation is a common and often perplexing problem for elderly people. The prevalence of self-reported constipation and factors associated with constipation were investigated in 3,166 people over age 65. Twenty-six percent of women and 15.8% of men reported recurrent constipation (p less than 0.0001). There was a significant increase in reported constipation with increasing age (p less than 0.0001). Multiple factors were found to correlate with self-reported constipation. A logistic regression model revealed 13 factors of significance in predicting constipation. The most important factors were age, sex, total number of drugs taken, pain in the abdomen, and hemorrhoids (p less than 0.0001). Specific drugs do not appear to be important factors in constipation in the elderly. Elderly people who report the use of multiple drugs, pain in the abdomen, and hemorrhoids are at increased risk for constipation.

A fluoride dose-response evaluation in an anticaries clinical trial

This study evaluated the dose-response relationship between four increasing levels of fluoride from 1000 to 2500 ppm F as sodium monofluorophosphate (MFP) and three-year dental caries increments, as measured by DMFS, DMFT, and DFS-A on 4424 schoolchildren. The results indicated consistent linear decreases in all three dental indices as the dose level increased to 2500 ppm F MFP, with slopes (average reductions) of 0.32 in DMFS for an increase of 1000 ppm F, 0.13 in DMFT, and 0.17 in DFS-A when all children were evaluated, p less than 0.03 for each index. For children 11 years and older at baseline, the slopes quadrupled, p less than 0.01 for each index. Age and baseline DMFS were shown to be the most important covariates to control for in the statistical models. No differences in adverse reactions, or other safety problems, were observed at the different dose levels.

Predictive power of various models for longitudinal attachment level change

Several statistical models that have been suggested in the periodontal literature for describing longitudinal attachment level changes, such as the gradual loss, single-burst, multiple-burst, and random walk models as well as other models introduced in this paper are compared by their power to predict future attachment loss. The data used in this analysis is from 1061 sites of 8 subjects, with moderate to severe periodontal disease, monitored monthly for about a year. This study found that none of the suggested models could significantly outperform the naïve mean predictor, which predicts the future attachment level from the past mean. It was also found that no single model, such as the burst, gradual, or random walk, together with measurement error can fully explain the variation in the data. These results indicate that in the course of one year, the attachment level change may not follow the same model. Consequently, a model that fits well to past data cannot be accurately extended to the future.

The effect of 3 mouthrinses on plaque and gingivitis development

The aim of this study was to evaluate the effect of 3 mouthrinses, Listerine Antiseptic (thymol), Peridex (chlorhexidine), Perimed (povidone iodine and hydrogen peroxide), and a placebo (water) on the development of dental plaque and gingivitis, when used as the only oral hygiene procedure for 14 days. 71 subjects were entered into a randomized, double-blind study. At the baseline examination, papillary bleeding score (PBS), and plaque index (PI) were registered, after which subjects received supragingival prophylaxis and were assigned to 1 of 4 study cells. Subjects were asked to refrain from all oral hygiene procedures except for the supervised 14-day 2 x daily rinsing with the assigned preparation. At day 14, the same clinical parameters were again registered. Statistical analysis was performed by a one-way analysis of variance (ANOVA) to compare the 4 groups, followed by Duncan's multiple range test to determine specific group differences. At baseline, average PBS and PI scores were similar for all 4 groups. After 14 days, the average PBS for Peridex and Perimed was significantly lower than for Listerine Antiseptic and water. The frequency of interdental units with a PBS greater than 2 was significantly lower for Peridex and Perimed than for Listerine Antiseptic and water. We concluded that both Peridex and Perimed were effective in reducing plaque and gingivitis when used as a 2 x daily mouthrinse by subjects refraining from other oral hygiene procedures. In vitro, a synergistic effect was assumed when inhibition was achieved with Perimed at the same or greater dilution than was achieved with povidone-iodine alone.

Reproducibility of attachment level measurements with two models of the Florida Probe

Clinical assessment of the progression of periodontitis is based on the measurement of periodontal probing attachment levels over time. In calculating these changes, duplicate measurements from fixed reference points, including cemento-enamel junctions and acrylic stents, have been used to assist in detecting progressive disease. The Florida Probe has been previously shown to improve the reproducibility of these measurements when used with an acrylic stent. The objective of the present study was to evaluate the reproducibility of 2 models of the Florida Probe, the original stent model and the modified disk model, in measuring attachment level. The disk probe differs from the stent probe in that it uses the occlusal surface of the tooth as a static reference point in calculating changes in attachment level measurements. In 10 subjects, sites were probed 2 x by 2 examiners using both types of probe. Standard deviations and intra- and inter-examiner correlations were calculated. These results demonstrate that the new disk probe yields reproducible measurements similar to the stent probe and is therefore suitable for use in longitudinal clinical studies.

Progression of visual acuity after penetrating keratoplasty

A consecutive series of 721 eyes was followed for visual acuity changes after keratoplasty in four groups: keratoconus, Fuchs' dystrophy, pseudophakic bullous keratopathy with retained intraocular lenses, and aphakic/pseudophakic bullous keratopathy with secondary implants during keratoplasty. Follow-up ranged from 12 to 84 months. Keratoconus eyes showed the quickest recovery of visual acuity: by 12 months, 91% attained a best-corrected vision of 20/40, and the mean lines of visual acuity for the group plateaued thereafter. The other three groups showed continuing improvement in vision through 24 months. From 3 months through 3 years after keratoplasty, the keratoconus and Fuchs' groups consistently showed better visual acuity levels than either the retained or the secondary implant groups (P less than 0.0001). Reporting changes in visual acuity over time offers multiple advantages compared with providing best-attained or last-recorded visual acuities after keratoplasty.

Evaluation of statistical methods for monitoring periodontal disease

Three methods for detecting the progression of periodontal disease based on the change in attachment level on teeth are compared from a statistical point of view. Regardless of gradual or burst disease progression theories, the regression method is found to be the most efficient way to detect changes. The exact false alarm rate is computed when the decision is based on the maximum regression coefficient at all sites during several visits.

Immune modulation of Prevotella intermedia colonization in squirrel monkeys

Colonization of the gingival crevice by black-pigmented Porphyromonas or Prevotella spp. (BP/P), including Porphyromonas gingivalis (formerly Bacteroides gingivalis) and Prevotella intermedia (formerly Bacteroides intermedius), is thought to be an important ecological event which may result in the destruction of connective tissues supporting the teeth. Theoretically, periodontal diseases could be prevented if these or other periodontal pathogenic microorganisms did not colonize the subgingival area. The humoral immune response is one mechanism which may modulate bacterial colonization in the gingival crevice. In the present study, we tested the effect of systemic humoral immunity on subgingival colonization by indigenous P. intermedia in squirrel monkeys (Saimiri sciureus). Animals rendered essentially free of detectable BP/P by a single scaling, 10 days of tetracycline therapy, and toothbrushing three times per week were immunized with P. intermedia 1447 or were sham immunized with phosphate-buffered saline. Subsequently, all oral hygiene procedures were discontinued and five teeth in one quadrant were ligated with bacterium-soaked suture material to facilitate BP/P colonization. Immunization resulted in a significant increase in the level of immunoglobulin G anti-P. intermedia antibody in serum. Two weeks after ligation was initiated, P. intermedia could be detected in five of six sham-immunized and three of six immunized animals. Immunization was associated with a reduction in the emergence of indigenous P. intermedia in the gingival crevice.

Clinical, microbiological and immunological characteristics of subjects with "refractory" periodontal disease

The aim of the present study was to analyze the relationship between attachment loss and clinical, microbiological, and immunological parameters in a group of 21 human subjects exhibiting poor response to previous periodontal therapy. All had been treated with periodontal surgery, tetracycline, and subsequent maintenance recalls to periodontists who, upon detection of disease progression, referred the subjects to our clinic. In our clinic, each subject received oral hygiene instruction and a thorough subgingival scaling and root planing utilizing as many appointments as necessary. Clinical indices, including gingival index, bleeding on probing, suppuration, plaque index, pocket depth, and duplicate measurements of attachment level from an acrylic stent, were collected at monthly intervals. Probing measurements were performed using the Florida Probe. When significant attachment loss (0.8-1.2 mm) was detected in at least 1 site, a bacterial sample was taken from that site and from a comparably deep, but non-progressing, control site. Microbial samples were enumerated by darkfield microscopy, on selective and non-selective media, and by predominant cultivable technique. Blood samples were also collected to determine antibody levels against potential pathogens. There was no difference in the amount of plaque present in sites gaining or losing attachment, but losing sites exhibited more bleeding and suppuration. 20 of the 21 subjects were tested; of these, 17 exhibited elevated serum antibody against one or more of the following microorganisms: Actinobacillus actinomycetemcomitans, Bacteroides, gingivalis, and Eikenella corrodens. However, few, if any, of the "classical" pathogens were detected in the plaque samples obtained at the time progressive disease was diagnosed. The only exception was Streptococcus intermedius, which occurred in slightly higher numbers in active sites.

Changing patterns of therapeutic agents in the elderly: a ten-year overview

Drug use patterns in a large ambulatory elderly population were studied cross-sectionally over a 10-year period. There were 24192 drug histories obtained on 4509 individuals during the period from 1 August 1978 to 31 July 1988. The average number of drugs used per person increased from 3.22 in 1978-9 to 3.94 in 1987-8. Prescribed drug use increased by 0.52 per person compared with an increase of 0.21 for nonprescribed medication. Analysis of two mutually exclusive groups of participants from 1978-9 and 1987-8 revealed a significant (p less than 0.0001) increase in the use of nonprescribed medication but no significant increase in the use of prescribed medication after adjusting for age and sex effects. The four most frequently used therapeutic classes of drugs in 1978-9 as a percentage of all drugs used were antihypertensives (10.8%), analgesic-antipyretics (6.4%), antirheumatic (6.4%), and cathartics (5.4%) compared with the antihypertensives (9.5%), analgesic-antipyretics (5.9%), anticoagulants (5.5%), and antirheumatic (4.6%) for the 1987-8 period.

Graft survival in four common groups of patients undergoing penetrating keratoplasty

Graft survival rates and causes of graft failure were evaluated for 1046 consecutive keratoplasties in four groups: keratoconus, Fuchs' dystrophy, pseudophakic bullous keratopathy with retained intraocular lenses (IOLs), and pseudophakic/aphakic bullous keratopathy with secondary lens implants. Patient follow-up averaged 23 months (range, 1-84 months). There was a significant difference in graft survival among the four groups, P less than 0.0001. The keratoconus and Fuchs' groups had the highest survival rates and pseudophakic bullous keratopathy with retained IOLs the lowest rate. Problems with the external surface of the graft caused the largest number of graft failures. Grafts for pseudophakic bullous keratopathy with retained posterior chamber lenses had a significantly higher failure rate from rejection and endothelial decompensation, 5.1%, compared with less than 1.0% in keratoconus, Fuchs' dystrophy, or bullous keratopathy with secondary implants (P less than 0.0005).

Effect of psyllium hydrophilic mucilloid on serum cholesterol in the elderly

The effect of psyllium hydrophilic mucilloid (PHM) when used as a laxative and/or stool softener on serum cholesterol concentrations was examined in 176 ambulatory elderly participants attending a health screening program. The change in one-year serum cholesterol concentration in subjects using PHM was compared with the change in cholesterol in 741 participants who did not report the use of PHM. Serum cholesterol concentration decreased by 0.073 mmol/liter (2.82 mg/dl) in the treatment group compared with a decrease of 0.036 mmol/liter (1.39 mg/dl) in the control group. After adjusting for confounding factors, excluding psyllium dose, by using a multiple regression model there was no significant difference in the change in serum cholesterol concentration (P = 0.935). PHM dosage information was available for 158 participants. After adjusting for baseline serum cholesterol and confounding factors using multiple regression analysis, it was found that the dose of PHM administered was significantly correlated with the change in serum cholesterol (P = 0.0120). For every 1-g increase in daily PHM dose there was a 0.022 mmol/liter (0.84 mg/dl) decrease in serum cholesterol concentration.

A longitudinal evaluation of drug use in an ambulatory elderly population

Participants in a geriatric health screening program were studied longitudinally to determine the patterns of drug use over a 10 year period. There were 314 (34.0%) men and 610 (66.0%) women who completed 10 yearly health screening evaluations. The mean number of prescribed and non-prescribed drugs used per participant increased from 2.90 in 1978-79 to 4.08 in 1987-88 (p less than 0.0001). There was no significant difference between men and women in the rate of increased drug use. There was no significant increase in the mean number of drug ingredients per participant used over the 10 year period. The most frequently reported therapeutic categories for 1978-79 were antihypertensives, analgesic-antipyretics, antirheumatics, multiple vitamins, cathartics and vitamin E, which represented 10.2, 7.2, 6.5, 4.9, 4.8 and 3.8% of all categories used. There was a decline in all of these categories between interval 1 and 10. Increased use of drugs, particularly prescribed medications, by the elderly population may present problems of adverse drug reactions, drug interactions and medication compliance in the future. Changing patterns of drug use may have resulted, in part, from introduction of new therapeutic classes and from new treatment concepts over the 10 year study period.

Correlates of cognitive dysfunction in an ambulatory elderly population

Mini-Mental State Examination (MMSE) scores were studied in an ambulatory elderly population to identify correlates with self-reported signs, symptoms, diseases, drugs and laboratory values. A total of 1,264 subjects were studied including 844 women and 420 men. In this study, 5.0% of men and 5.3% of women scored less than 24 on the MMSE. A linear-regression model revealed eleven factors of significance in predicting scores on the MMSE. The most important predictors were age (p less than 0.0001), self-reported memory loss (p less than 0.0001), complaints of swollen feet or ankles (p less than 0.0010), the total number of diseases reported (0.0006) and the serum lactate dehydrogenase concentration (p less than 0.0098). Results suggest that cognitive function in the elderly is not related to the general level of health or consistently affected by specific disease states.

Effect of non-surgical periodontal therapy combined with adjunctive antibiotics in subjects with "refractory" periodontal disease. (I). Clinical results

The aim of the present study was to evaluate the clinical effect of non-surgical periodontal therapy with the adjunct of a selected antibiotic in subjects with refractory periodontitis. 10 subjects were selected for the study; all had a history of periodontal surgery, tetracycline therapy, and regular maintenance by a periodontist. Clinical registrations including gingival index, plaque index, presence of bleeding and suppuration, pocket depth, and duplicate measurements of attachment level were performed at baseline and at monthly intervals. When disease activity was detected based on the tolerance method, a bacterial sample was taken from the active site and its susceptibilities to a number of antibiotics were determined. For the selected 10 subjects, Augmentin was the antibiotic of choice. Each subject received 750 mg/day for 2 weeks, during which time a full-month scaling and root planing was performed under local anesthesia. Clinical re-evaluation was performed after 3, 6, 9 and 12 months. At the time disease activity was detected, the average loss of attachment at all active sites was 2.2 mm, and the increase in pocket depth 1.5 mm. At 3 months post-therapy, these sites had regained 2 mm of attachment which remained stable through the 12-month examination. Pocket depths decreased 2.5 mm over the first 6 months and then stabilized. The frequency of all sites that gained 1 mm or more of attachment increased by approximately 10% over the first 9 months following therapy. The frequency of all sites that decreased 1 mm or more in pocket depth increased approximately 15% over the same period.(ABSTRACT TRUNCATED AT 250 WORDS)

Efficacy of Perimed antibacterial system on established gingivitis. (I). Clinical results

A 6-month, double-blind controlled study was conducted on 101 subjects to determine the effect of Perimed antibacterial system, containing povidone-iodine (PVP-I) and hydrogen peroxide (H2O2), on established gingivitis. Subjects were randomly assigned to one of 4 treatment groups: PVP-I/H2O2, PVP-I/H2O, H2O2/H2O or H2O. Gingivitis was assessed by the papillary bleeding score (PBS) and plaque by a modified Quigley-Hein plaque index (PI) at baseline, 3, 12 and 24 weeks. The average baseline PBS and PI for the 4 groups ranged from 2.16-2.31 and 2.87-2.90, respectively. After baseline evaluation, subjects received a supra-gingival scaling and a subgingival irrigation with their respective rinse. Daily rinses were supervised and subgingival irrigation was repeated every 3 weeks. Duncan's multiple range test determined which groups differed from each other. The mean PI at 24 weeks was lower than at baseline in all groups. PVP-I had the lowest PI at all time points. The mean PBS at 24 weeks was 1.48 for PVP-I, 1.62 for H2O2, 1.88 for H2O and 1.34 for PVP-I/H2O2, a reduction from baseline of 31%, 27%, 18%, and 38% respectively. The difference between the PBS for PVP-I/H2O2 and H2O control was significant at each evaluation. There was a 70% reduction in sites with PBS greater than or equal to 3 for PVP-I/H2O2 between baseline and 24 weeks compared to a 34% decrease in the H2O group. It was concluded that the use of Perimed could be a beneficial adjunctive treatment for the prevention and control of gingivitis when used with routine oral hygiene procedures.

Incidence of hypertension in an ambulatory elderly population

Investigations of the natural history of blood pressure have generally evaluated mean systolic and diastolic pressure changes. While information, this information is not directly applicable to clinical practice settings, in which patients are usually classified as normotensive or hypertensive. We measured the actual incidence of hypertension, using two different definitions, in an ambulatory elderly population of 2,584 individuals over an 8-year period. Using the less stringent blood pressure definition (systolic blood pressure greater than 140 mmHg and diastolic blood pressure greater than or equal to 90 mmHg), 884 (34.2%) participants were normotensive and 1,700 (65.8%) were hypertensive at an initial screening. The average annual incidence of hypertension over the subsequent eight years was 13.2%, and life tables demonstrated a gradual risk of developing hypertension. The development of hypertension was not associated with gender or age; while older age groups had a greater chance of developing hypertension than younger, the difference did not reach statistical significance.

Modulation of colonization by black-pigmented Bacteroides species in squirrel monkeys by immunization with Bacteroides gingivalis

Periodontal diseases are inflammatory responses thought to be triggered by specific microorganisms colonizing in the gingival crevice. Theoretically, periodontal diseases could be prevented if the etiologic organisms were not allowed to colonize the subgingival area. The humoral immune response is one mechanism which may modulate bacterial colonization in the gingival crevice. To test the effect of systemic humoral immunity on subgingival colonization by bacteria, squirrel monkeys (Saimiri sciureus) were immunized with Bacteroides gingivalis, a black-pigmented Bacteroides sp. and putative periodontal pathogen. Immunized and sham-immunized monkeys were orally inoculated with 10(10) viable B. gingivalis during ligation of five teeth in one quadrant with bacterium-soaked suture material and distribution over the entire dentogingival margin. Immunization resulted in an increased level of immunoglobulin G anti-B. gingivalis in serum and was associated with a strong trend toward a statistically significant reduction in colonization of the gingival crevice by black-pigmented bacteroides.

Visual, refractive, and keratometric results of radial keratotomy. Five-year follow-up

This article presents five-year findings on the first 156 radial keratotomies in our series. Results are compared with findings on these same eyes at one and three years and with results from other studies. Follow-up at five years was on 123 eyes (79%). Before surgery, the mean spherical equivalent was -5.0 diopters (D). Five years after surgery, the mean change in the spherical equivalent was 5.17 D, and 53% of eyes were within 1 D of emmetropia. Uncorrected visual acuity was 20/200 or worse in 96% of eyes before surgery. At five years, 36% had 20/20 acuity or better, and 75% were 20/40 or better. Best corrected acuity was at least 20/20 in 90% of eyes before surgery. At five years, 85% retained at least 20/20 best corrected acuity. Although some patients still have shown refractive and visual acuity changes through five years after surgery, the overall group has been stable.

Five-year results of radial keratotomy

We present 5-year findings on 198 consecutive radial keratotomy surgeries. Follow-up was obtained on 134 (68%) of these eyes. Mean spherical equivalent (SE) was -4.3 diopters before surgery, average keratometry was 44.11 D, and 75% of eyes had uncorrected distance acuity of 20/400 or worse. Average SE was -0.52 D for eyes seen at 5 years, which compares with -0.78 D for eyes examined at 18 months. Seventeen percent of eyes show at least a 1-D change in refraction from 18 months to 5 years compared with 13% between 18 months and 3 years. Fifty-six percent of eyes are within 1 D of emmetropia at 5 years, compared with 66% at 18 months. Uncorrected visual acuity was at least 20/40 in 62% of eyes seen at 5 years and in 73% of eyes seen at 18 months. Ten percent of eyes have lost at least two lines of best-corrected visual acuity from before surgery to 5 years later. Factors are identified that relate to loss of uncorrected and best corrected acuity over 5 years. Average keratometry at 5 years is 40.7 D, as compared with 41.2 D at 18 months. Long-term keratometric results appear less stable than refractive results and a theory for this instability is presented. The results indicate radial keratotomy to be safe and effective for the vast majority of patients in this series for 5 years postoperatively.

Resting heart rates in an ambulatory elderly population: an evaluation of age, sex, symptoms, and medication

In a cross-sectional analysis of 2,301 ambulatory elderly subjects, the mean resting heart rate for women (66.2/min) was significantly higher than for men (63.6/min), p less than 0.0001, and heart rate was positively correlated with age for both men and women. Resting heart rate was positively correlated with the number of drugs used (p less than 0.05), number of symptoms reported (p less than 0.05), systolic (p less than 0.01), and diastolic (p less than 0.0001) blood pressure. Of 975 participants who were followed longitudinally over an 8-year period there was a significant decrease in resting heart rate of approximately 2.75/min, p less than 0.0001.

Interactions between statisticians and biomedical journal editors

The increased involvement of statisticians in the publication of biomedical research has resulted in increased communication between statisticians and biomedical journal editors. This paper considers ways to enhance positive interactions between statisticians and journal editors. Specific questions addressed are: What are the most serious statistical problems in manuscripts? What statistical design information should the methods include? How can editors identify papers that need statistical review? How can editors interpret what statistical reviewers say? How can editors identify statisticians who are willing to review manuscripts?

A 3-year clinical trial to compare efficacy of dentifrices containing 1.14% and 0.76% sodium monofluorophosphate

A 3-yr daily supervised toothbrushing study with a double blind design was conducted to evaluate the anticaries effectiveness of a 1.14% sodium monofluorophosphate (MFP) dentifrice (1500 ppm F) compared to a 0.76% MFP dentifrice (1000 ppm F). This study began with nearly 4000 children, primarily aged 8-11, in grades 3-5, residing in a nonfluoridated community in Florida. A total of 2415 children completed 3 yr of the study, representing 61% of the children who began the study. The results indicate a statistically significant (P less than 0.001) anticaries benefit was derived over a 3-yr period from the use of the higher fluoride dentifrice (1500 ppm F) when compared to the positive control (1000 ppm F). Percent reductions in mean dental caries increments were 20.9%, 22.1%, 21.8%, 24.3%, and 35.2% for DMFT, DFT, DMFS, DFS, and DFS Interproximal, respectively.

Two-year results of reoperations for radial keratotomy

This study compared the two-year results of 320 radial keratotomy surgeries that did not result in reoperations with those of 67 cases that had reoperations. Follow-up was 76% for cases not reoperated and 79% for reoperated cases. Eyes that had reoperations averaged 2.2 diopters more initial myopia than eyes that did not have reoperations, and they averaged 43% myopia correction in the first surgery vs 84% for eyes that did not require reoperations; the reoperation corrected an additional 47% of residual myopia, for an overall 70% correction of myopia in the two surgeries. These results indicated that twice the desired effect of correction should be attempted in a reoperation to achieve the desired result.

Attachment level measurements with a constant force electronic probe

The purpose of the present investigation was to evaluate the reproducibility of probing attachment level measurements using a newly developed constant force electronic probe. The probing force was preset at 25 g (probe diameter 0.4 mm) and was connected to a computer through a variable differential transformer. The measurements were performed on 10 patients with minimal signs of periodontal disease, using individually made acrylic stents. When the probe was in place and a foot switch depressed, the measurement was stored on the computer to the nearest 0.1 mm. The measurements were performed by one periodontist and one hygienist during one visit, and were then repeated by the same periodontist and another hygienist during a second visit. The results showed high correlations between the periodontist and the hygienist during one visit, between the two visits for the periodontist, and between the two hygienists at two different visits. The subject threshold for attachment loss was calculated according to Haffajee and co-workers, and was found to average 0.84 mm for the measurements performed by the periodontist and the hygienist during the same visit. For the periodontist during two separate visits and for the two different hygienists, the average threshold was 0.99 and 1.02 mm, respectively. Duplicate measurements were also performed by one periodontist at one visit on 10 patients with advanced periodontal disease. The average subject threshold for these patients was 0.60 mm. It may be concluded that with the constant force electronic probe, loss of attachment can be detected earlier than when conventional instruments are used.

Correlation between electronic and visual readings of pocket depths with a newly developed constant force probe

The purpose of this study was to compare probing measurements obtained using a newly developed constant force electronic probe, which eliminates errors of visual reading and variable force, to those obtained using a standard periodontal probe. The probe was connected to a digital readout through a linear variable differential transformer; the digital readout was connected to a printer and a foot switch. When the probe was in position and the foot switch depressed, the pocket depth was printed to the nearest 0.1 mm. 12 subjects with minimal to early periodontitis were selected for the study. The pocket depths of each patient were recorded electronically utilizing a constant force of 25 g, and conventionally using the same instrument in a "locked" position and visual reading. Probings were performed on each subject by 3 different examiners, on 3 separate occasions 2-3 days apart. The results showed a high correlation between manual and electronic probing. The average correlations for the 3 investigators between examinations were consistently higher for the electronic probings. In comparing the 3 examiners to each other, consistently higher correlations were found for the electronic pocket readings. Correlations for single-rooted teeth were lower for all 3 examiners. The pocket depth measurements recorded when using the manual probe with visual readings were consistently deeper than those obtained using the electronic probe with computer readings. It was concluded that the reproducibility of measurements obtained with the electronic probe was significantly superior to that obtained with a manual probe.