The Reporting of Statistical Inferences in Selected Prosthodontic Journals

Abstract

Dental periodicals are the fundamental source of prosthodontic research. The ability to understand and contribute to dental literature is basic to the prosthodontic profession. The purpose of this study is to tally relative frequency with which various descriptive (n = 18), graphical (n = 7), and inferential statistical procedures (n = 68) are used in the prosthodontic literature. Our method consists of four procedures: journal selection, choice of 1987 through 1988 articles with inferential statistical content, tally of the statistical procedures in those articles, and quality control procedures used in obtaining these data. At least 50% of 10 prosthodontists selected 17 of 100 journals most likely to be read by prosthodontists. In the 17 journals, 1,320 articles were screened of which 406 were selected and evaluated for their statistical procedures. The bar and line plots were the most common graphical procedures occurring in over one fourth of the 406 articles. Percentages, means, and standard deviations occurred in more than 40%. Although 58% used the .05 significance level, only 0.3% mentioned power. Analysis of variance was used more often than the t tests (42% v 29%), whereas correlation/regression (21%) and chi-square tests (14%) were used less often. The t tests, analysis of variance (Duncan, Tukey, and Student-Newman-Keuls multiple comparison procedures), chi-square tests, correlation and regression, and the Wilcoxon tests occurred in at least 5% of the 406 articles.

Are Sample Sizes Clear and Justified in RCTs Published in Dental Journals?

“…A relatively recent review based on six high impact factor medical journals revealed that sample size calculations are inadequately reported and often based on inaccurate assumptions [3]. Suboptimal reporting has also been found in studies published within dentistry [14], [15], [16], [17], [18], [19], [20], [21]. In addition to lack of reporting or incomplete reporting of sample size calculations, further issues include whether the recruited numbers are calculated correctly based on the preset assumptions, and whether those a priori assumptions hold for the observed results [3].…”

Mislabeling Controlled Clinical Trials (CCTs) as “Randomized Clinical Trials (RCTs)” in Dental Specialty Journals

“…[1][2][3][4][5] Among the various study designs, the randomized clinical trial is considered the design that has the potential to provide the highest quality evidence 1 ; however, there is substantial evidence in the biomedical literature, including dentistry, that randomization and RCT quality, in general, is suboptimal and that often clinical trials described as RCTs are not really RCTs. 4,5,[16][17][18][19][20][21][22][23][24][25][26][27] The term randomized clinical/controlled trial has become more common during the past decade in the titles of articles published in dental journals; however, no study exists that assesses whether studies representing the major dental specialties and published as RCTs are truly RCTs. Therefore, the purpose of this study was to investigate the extent to which studies published in major dental journals using the term RCTs in the title are possibly mislabeled, based on their reporting, and to identify possible associations between journal type and other publication characteristics, such as the involvement of a statistician, the time since publication, the number of authors, the origin of the study, and the parties involved in the study (single or multicenter), on correct classification.…”

Reporting of Research Quality Characteristics of Studies Published in 6 Major Clinical Dental Specialty Journals

“…Confounding and bias are distinct entities, and unlike bias, confounding can be evaluated quantitatively and controlled for during the design of the trial by ensuring equal distribution of risk factors and during the analysis of the study through stratification and multivariate regression analysis. 23 In the dental literature, a small number of studies have reported on study quality characteristics mainly of randomized clinical trials in periodontics, 24,25 prosthodontics, [26][27][28] implantology, 29 orthodontics, 30 and dentistry. 31 There is a lack of studies reporting on quality characteristics of dental research across dental specialty journals and across all types of study designs.…”