Using Research for Clinical Decision-Making: Elements of a Research Report
Course Number: 45A
The Results
The Results should present the findings of the study related to each research question or hypothesis without explanation.^{3} A summary of the numerical findings or data should be presented in tables, while figures should provide a pictorial representation of the data in graphs, illustrations, photographs, and micrographs (photos of objects seen through a microscope). Table 1 often summarizes the baseline characteristics (descriptive statistics) of the sample. In a randomized controlled trial, such as the dentifrice example here, this table is important in demonstrating the equivalence of the experimental groups in their baseline characteristics. Data in subsequent tables usually address the main research hypotheses. The text describes the most important findings.
Below is an example of the Results section:
The Clinical Effect of Dentifrices Containing Stabilized Stannous Fluoride on Plaque Formation and Gingivitis - A Six-Month Study with Ad libitum Brushing^{4}
Results
Of the 620 subjects entered into the study, 542 were available for the three-month examination and 549 were available for the final six-month examination. These sample sizes represent the total for the four treatment groups studied. The presentation of results that follow excludes the scores for the experimental dentifrice group which had no bearing on the stannous fluoride comparisons. For the remaining groups, 463 subjects were included in the baseline examination, 412 subjects were included in the three-month examination, and 416 subjects were included in the final six-month examination.
The baseline demographics for those subjects who completed the three-and six-month examinations are given in Table 1. The means of the clinical baseline scores measured for these same subjects are given in Table 2. At both three and six months, there were no statistically significant differences among treatment groups with respect to baseline age, gender, plaque, stain, gingivitis, and gingival bleeding scores.
Table 1. Initial Demographic Balance for Subjects Completing the Indicated Portion of the Study | ||||||
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^{a}0.454% stannous fluoride stabilized with 2.08% sodium gluconate ^{b}0.454% stannous fluoride stabilized with 4.16% sodium gluconate |
Table 2. Initial Balance for Gingivitis, Gingival Bleeding, Plaque, and Stain for Subjects Completing the Indicated Portion of the Study | ||||||
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* SEM is the standard error of the mean ^{a} 0.454% stannous fluoride stabilized with 2.08% sodium gluconate ^{b} 0.454% stannous fluoride stabilized with 4.16% sodium gluconate |
The three-and six-month covariance-adjusted mean gingivitis scores and corresponding percent reductions between control and treatment groups are given in Table 3. Relative to the control group, statistically significant reductions in gingivitis of 14.6% and 16.7% were observed at three months for the lowGluc and highGluc stabilized stannous fluoride dentifrices, respectively. At six months, relative to the control group, statistically significant reductions in gingivitis of 18.8% and 18.0% were seen for the lowGluc and highGluc stabilized stannous fluoride dentifrices, respectively. No significant differences in gingivitis effects were observed between the two stannous fluoride dentifrices.
Table 3. Covariance-Adjusted Three and Six Month Gingivitis Results | ||||
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Covariance Adjusted Error Mean Square = 0.0271. Means within brackets are not significantly different at alpha = 0.05 using the 2-tailed Student-Newman-Keuls test. *No tooth covers employed at this examination. | ||||
Covariance Adjusted Error Mean Square = 0.0359. Means within brackets are not significantly different at alpha = 0.05 using the 2-tailed Student-Newman-Keuls test. **Tooth covers were employed at this examination. |
The three-and six-month covariance-adjusted mean gingival bleeding scores and corresponding percent differences between control and treatment groups are given in Table 4. After three months of use, the lowGluc and highGluc stabilized stannous fluoride dentifrices reduced gingival bleeding, relative to the control group, by 27.9% and 20.2%, respectively. Following six months of use, the lowGluc and highGluc stabilized stannous fluoride dentifrices reduced gingival bleeding, relative to the control group, by 30.5% and 23.1%, respectively. However, these differences were not statistically significant at alpha = 0.05.
Table 4. Covariance-Adjusted Three and Six Month Gingival Bleeding Results | ||||
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Covariance Adjusted Error Mean Square = 45.3027. Means within brackets are not significantly different at alpha = 0.05 using the 2-tailed Student-Newman-Keuls test. | ||||
Covariance Adjusted Error Mean Square = 45.3027. Means within brackets are not significantly different at alpha = 0.05 using the 2-tailed Student-Newman-Keuls test. |
Three-and six-month covariance-adjusted plaque scores are given in Table 5. At both three and six months, non-significant reductions in plaque scores, relative to the control group, were observed for both the lowGluc and highGluc stabilized stannous fluoride dentifrices.
Table 5. Covariance-Adjusted Three and Six Month Stain Index Results | ||||
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Covariance Adjusted Error Mean Square = 0.0998. Means within brackets are not significantly different at alpha = 0.05 using the 2-tailed Student-Newman-Keuls test. | ||||
Covariance Adjusted Error Mean Square = 0.0799. Means within brackets are not significantly different at alpha = 0.05 using the 2-tailed Student-Newman-Keuls test. |
Three-and six-month covariance-adjusted stain scores are presented in Table 6. Clinically measured stain was significantly increased for the stannous fluoride groups at both the three-and six-month examinations.
Table 6. Covariance-Adjusted Three and Six Month Stain Index Results | |||
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Covariance Adjusted Error Mean Square = 15.5491. Means within brackets are not significantly different at alpha = 0.05 using the 2-tailed Student-Newman-Keuls test. | |||
Covariance Adjusted Error Mean Square = 20.9946. Means within brackets are not significantly different at alpha = 0.05 using the 2-tailed Student-Newman-Keuls test. |
There were no significant differences with respect to clinical stain between the two stannous fluoride groups. The six-month hygienist stain assessment, ease of stain removal, and total post-study prophylaxis times are shown in Tables 7a, 7b, and 7c, respectively.
Table 7. Hygienist Stain Rating (7a), | ||
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Table 7a. Hygienist Stain Rating | ||
For stain rating, scores ranged from 0 to 6 in increments of 1 where 0 = none; 2 = slight; 4 = moderate; 6 = severe. Analysis of variance conducted using a model that contained hygienist, treatment, and hygienist by treatment as factors. Means within brackets are not significantly different by the Student-Newman-Keuls test at alpha = 0.05. | ||
Table 7b. Ease of Stain Removal | ||
For ease of stain removal, scores ranged from 1 to 5 where 1 = easy;
2 = moderately easy; 3 = average; 4 = moderately difficult; 5 = difficult. Analysis of variance conducted using a model that contained hygienist, treatment, and hygienist by treatment as factors. Means within brackets are not significantly different by the Student-Newman-Keuls test at alpha = 0.05. | ||
Table 7c. Timed Prophylaxis | ||
Analysis of variance conducted using a model that contained hygienist, treatment, and hygienist by treatment as factors. Means within brackets are not significantly different by the Student-Newman-Keuls test at alpha = 0.05. |
Hygienists reported observing significantly more stain for the stannous fluoride groups relative to the control group, though the absolute magnitude of the stain was rated as "slight" for both stannous fluoride groups. With respect to ease of stain removal, hygienists reported a slight increase in effort progressing from the control (1.78) to the lowGluc (2.16) and highGluc (2.38) stabilized stannous fluoride groups. The difference between the control and lowGluc stabilized stannous fluoride groups was not statistically significant. However, the difference between the control and highGluc stabilized stannous fluoride groups was statistically significant. Differences in the mean prophylaxis times between the control and stabilized stannous fluoride dentifrice groups were less than five minutes and were not statistically significant.
Examinations of the oral mucosa after three and six months revealed no unexpected or clinically serious adverse reactions to any of the test dentifrices.