False positive rates encountered in the detection of changes in periodontal attachment level

This thesis demonstrates that the assumption of normality used by Goodson results in the underestimation of the type I error rate of the tolerance method by a factor of 10. This underestimation is due to the positive kurtosis demonstrated in the distribution of replicate differences. Therefore, the assumption of normality does not seem warranted. It is shown here that a resampling technique more accurately estimates the type I error rate. The estimates of false positive rates have important implications in the field of periodontics. When diagnostic decisions are based on single measurements, false positive rates are high. Even when thresholds as high as 3 mm. are used, over 3 out of 10 sites identified as changed have not changed. Unfortunately, in the clinical practice of periodontics, single measurements are commonly used. Therefore, clinicians who make treatment decisions based on attachment level measurements, may be treating a large percentage of sites that have not undergone destructive periodontal disease. Clinical periodontists generally regard a loss of attachment of 3 mm. or more as evidence of progressively worsening disease requiring additional therapy. The consequences of treating areas that are erroneously concluded as having progressed have to be compared to the consequences of not treating areas that are progressing. If a clinician treats sites when a change of 3 mm. in attachment level is detected, it is likely that as many as 32% of the sites may not have progressed. However, if the change in attachment level is real and the site is not treated, a significant proportion of the attachment may be lost. Changes of 3 mm. are large compared to the length of the root of the tooth. Weine (1982, p. 208-209), using Black\u27s (1902) description of tooth anatomy, presents average root length of 13 categories of teeth. Average root lengths range from 12 to 16.5 mm. for the 13 categories. If a tooth with a root of 14 mm. (near the middle of the range of average tooth length) has a change in attachment level measurements of 3 mm., the clinician is faced with a dilemma as to whether the site should be treated. The dilemma is increased if prior to the change of 3 mm., the site had already lost 50% of its attachment. In this situation the 3 mm. change represents nearly half of the remaining attachment. For these reasons, better measurement techniques would be beneficial in the clinical practice of periodontics. A controversy exists in the periodontal literature on the ability of single attachment level measurements to find actual change in attachment level. Two recent reports are in general agreement with this study. Imrey (1986) evaluates the ability of single measurements of attachment level to find change in attachment level. He concludes: If true disease is uncommon and sensitivity to it is not high, these false positives may exceed in number the true positives detected (p. 521). Ralls and Cohen (1986) reach similar conclusions: the major issue is that \u27bursts\u27 of change can be explained by chance events which arise from measurement error and which occur at low but theoretically expected levels (p. 751). The results of the present research demonstrate that a large percentage of the perceived change in attachment level is due to measurement error, but not to the degree that Imrey (1986) and Ralls and Cohen (1986) suggest. These researchers attribute almost all the attachment level changes to measurement error. In contrast, Aeppli, D. M., Boen, J. R., and Bandt, C. L. (1984) reach a different conclusion: using an observed increase of greater than 1 mm. as a diagnostic rule leads to high sensitivity and yet satisfactorily high specificity (p. 264). All three of the above referenced studies base their conclusions on estimates of sensitivity and specificity. The methods of obtaining estimates of sensitivity and specificity vary between the studies. Aeppli, D. M., Boen, J. R., and Bandt, C. L. base their estimates of specificity and sensitivity on a calibration study involving 34 patients and 3 examiners. Their distribution of differences in replicated measurements is similar to the distribution that Goodson (1986) reports. Irnrey (1986) and Ralls and Cohen ( 1986), instead of using actual data, simulate the distribution of differences by using a normal approximation with standard deviations of 1.125 mm. and 1 mm. respectively. Even though the methods of obtaining data vary, all the reports obtain high values of specificity (Table 6). However, estimates of sensitivity vary both within and among the three studies. Table 6 demonstrates that for similar thresholds the studies obtain a wide range of estimates of sensitivity. Within each study estimates of sensitivity are shown to be highly dependent on the assumed magnitude of actual change and the threshold used to detect the change. As the threshold decreases or the assumed attachment level change increases, sensitivity increases. The possible wide range of estimates that can be obtained within a study is demonstrated by Ralls and Cohen (1986). Their estimates of sensitivity range from .0668 to .9772. As discussed in chapter 1, the broad range of estimates of sensitivity and those estimates\u27 basis on arbitrary assumptions brings to question their value

Dental Anatomy Carving Computer-Assisted Instruction Program: An Assessment of Student Performance and Perceptions

The purpose of this study was to compare the performance of students exposed to two different instructional modalities for dental anatomy wax carving: CAI (computer-assisted instruction) using DVD technology, or traditional laboratory instruction. Students’ self-assessment scores were also compared to faculty scores, and students’ perceptions of their teaching modality were analyzed. Seventy-three first-year dental students (response rate 81 percent) participated in this randomized single blind trial, in which faculty graders were blinded to student group assignment. There were no statistical differences, as determined by the Wilcoxon non-parametric test and a t-test, between the faculty grades on the wax carving from the two teaching methods the students experienced. The student self-assessments revealed higher mean grades (3.0 for the DVD-only group and 3.1 for the traditional group) than the faculty actual mean grades (2.2 for both the DVD-only group and the traditional group) by almost one grade level on a 4.0 grade scale. Similar percentages of students in the traditional group had either favorable or unfavorable perceptions of their learning experience, while more students in the DVD-only group reported favorable perceptions. Students from both groups said they wanted more faculty feedback in the course. Based on these objective and subjective data, merging CAI and traditional laboratory teaching may best enhance student learning needs

The Role of Leukocyte-Platelet Rich Fibrin in Human Alveolar Ridge Preservation: A Randomized Clinical Trial

PURPOSE: The aim of this study is to examine the healing of intact extraction sockets grafted with leukocyte-platelet rich fibrin (L-PRF) as compared to sockets grafted with freeze-dried bone allograft (FDBA) and a resorbable collagen barrier membrane (RCM). METHODS: This prospective randomized, examiner blinded pilot study included 17 subjects randomized to two treatment groups. Serum total cholesterol, low density lipoprotein (LDL), 25-hydroxyvitamin-D3, and platelet counts were determined preoperatively in all subjects. The experimental arm consisted of 8 posterior tooth-bounded intact extraction sites receiving L-PRF plugs. The control group consisted of 9 posterior tooth-bounded intact extraction sites receiving FDBA and RCM. An acrylic stent was fabricated to take duplicate clinical and CBCT measurements immediately post-extraction and at time of implant placement. A repeat-measures analysis of variance was utilized for statistical analysis. RESULTS: The study failed to detect a clinical or radiographic difference between treatment groups in horizontal or vertical ridge dimension changes. Serum cholesterol, LDL, 25-hydroxyvitamin-D3, and buccal plate thickness had a non-significant effect on outcome measurements, although there was a high prevalence of hyperlidpidemia and hypovitaminosis in the study population. CONCLUSIONS: The alveolar ridge dimension changes in intact posterior extraction sockets may be similar when either L-PRF or FDBA and RCM are utilized as socket grafting material. Although there was a high prevalence of high cholesterol and low 25-hydroxyvitamin-D3 levels in the population, this study failed to detect a significant correlation between preoperative serum levels and postoperative ridge dimension changes

Surgical Crown Lengthening: Evaluation of the Biological Width

Peer Reviewedhttps://deepblue.lib.umich.edu/bitstream/2027.42/141511/1/jper0468.pd

Faculty Impressions of Dental Students’ Performance With and Without Virtual Reality Simulation

This study compared faculty perceptions and expectations of dental students’ abilities using virtual reality simulation (VRS) to those who did not use virtual reality simulation (non-VRS) in an operative dentistry preclinical course. A sixteen-item survey with a ten-point rating scale and three open-ended questions asked about students’ abilities in ergonomics, confidence level, performance, preparation, and self-assessment. The surveys were administered three times to a small group of preclinical faculty members. First, faculty members (n=12, 92 percent response rate) gave their perceptions of non-VRS students’ abilities at the end of their traditional course. Secondly, faculty members (n=13, 100 percent response rate) gave their expectations of the next incoming class’s abilities (VRS students) prior to the start of the course with traditional and VRS components. Finally, faculty members (n=13, 100 percent response rate) gave their perceptions of VRS students’ abilities after completion of the course. A Tukey’s test for multiple comparisons measured significance among survey items. Faculty perceptions of VRS students’ abilities were higher than for non-VRS students for most abilities examined. However, the faculty members’ expectations of VRS training were higher than their perceptions of the students’ abilities after VRS training for most abilities examined. Since ergonomic development and technical performance were positively impacted by VRS training, these results support the use of VRS in a preclinical dental curriculum

Meta-analysis of the effect of an essential oil–containing mouthrinse on gingivitis and plaque

AbstractBackgroundStandard recommendations for oral hygiene practices have focused on mechanical methods (toothbrushing and interdental cleaning). Published evidence indicates antimicrobial mouthrinses provide oral health benefits beyond mechanical methods alone. The purpose of this meta-analysis was to evaluate the combined effectiveness of mechanical methods with essential oil–containing mouthrinses (MMEO) versus mechanical methods (MM) alone in achieving site-specific, healthy gingival tissue and reducing plaque and gingivitis.Types of Studies ReviewedAll industry-sponsored clinical trials investigating the antigingivitis and antiplaque effects of essential oil (EO)–containing mouthrinses conducted from 1980 to 2012 were reviewed; 29 of 32 studies met the inclusion criteria of 6 months or longer duration, randomized, observer-masked, placebo-controlled, and with individual-level site-specific data. By-study treatment effects were estimated through generalized linear models for binary data and analysis of covariance for continuous data, and then combined using standard meta-analysis techniques; heterogeneity was also assessed.ResultsSummary odds ratios for a healthy gingival site and for a plaque-free site were, respectively, 5.0 (95% confidence interval [CI], 3.3-7.5) and 7.8 (95% CI, 5.4-11.2) for MMEO participants versus MM participants at 6 months. The summary percentage reductions in whole-mouth mean gingivitis and plaque at 6 months were 16.0 (95% CI, 11.3-20.7) and 27.7 (95% CI, 22.4-32.9), respectively. Responder analyses using aggregate individual-level data showed 44.8% of MMEO participants and 14.4% of MM participants achieved at least 50% healthy sites in their mouths at 6 months. Similarly, 36.9% of MMEO participants and 5.5% of MM participants achieved at least 50% plaque-free sites in their mouths at 6 months.Conclusions and Practical ImplicationsThis is the first meta-analysis to demonstrate the clinically significant, site-specific benefit of adjunctive EO treatment in people within a 6-month period (that is, between dental visits)

Results From the Periodontitis and Vascular Events (PAVE) Study: A Pilot Multicentered, Randomized, Controlled Trial to Study Effects of Periodontal Therapy in a Secondary Prevention Model of Cardiovascular Disease

Background- In the Periodontitis and Vascular Events (PAVE) pilot study, periodontal therapy was provided as an intervention in a secondary cardiac event prevention model through five coordinated cardiac-dental centers. Methods- Subjects were randomized to either community care or protocol provided scaling and root planing to evaluate effects on periodontal status and systemic levels of high-sensitivity Creactive protein (hs-CRP). Results- After 6 months, there was a significant reduction in mean probing depth and extent of 4- or 5-mm pockets. However, there were no significant differences in attachment levels, bleeding upon probing, or extent of subgingival calculus comparing subjects assigned to protocol therapy (n = 151) to those assigned to community care (n = 152). Using intent-to-treat analyses, there was no significant effect on serum hs-CRP levels at 6 months. However, 48% of the subjects randomized to community care received preventive or periodontal treatments. Secondary analyses demonstrated that consideration of any preventive or periodontal care (i.e., any treatment) compared to no treatment showed a significant reduction in the percentage of people with elevated hs-CRP (values >3 mg/l)at 6 months. However, obesity nullified the periodontal treatment effects on hs-CRP reduction. The adjusted odds ratio for hs-CRP levels >3 mg/l at 6 months for any treatment versus no treatment among non-obese individuals was 0.26 (95%confidence interval: 0.09 to 0.72), adjusting for smoking, marital status, and gender. Conclusion- This pilot study demonstrated the critical role of considering obesity as well as rigorous preventive and periodontal care in trials designed to reduce cardiovascular risk. Originally published Journal of Periodontology, Vol. 80, No. 2, Feb 200