Not enough SPIRIT shown in the registration and reporting of orthodontic trial protocols.

BACKGROUND: To reduce bias associated with selective reporting, the registration and publication of clinical trial protocols before or at the time of patient enrolment has been advocated. The aim of this investigation was to assess the frequency of registration and reporting adherence of orthodontic trial protocols pre- and post-introduction of the Standard Protocol Items Recommendations for Interventional Trials (SPIRIT) Statement. MATERIALS AND METHOD: Trial protocols registered in four online registries were sourced at two time periods: (1 January 2010-1 January 2013) and (1 January 2017-1 January 2021). Protocols were screened and data extracted, in duplicate and independently. The reporting adherence of each protocol was assessed in relation to the thirty-three item SPIRIT statement. Fisher's exact test was used to determine associations between time periods and trial protocol characteristics. Median regression was implemented to assess potential associations between the percent score per protocol and protocol characteristics. RESULTS: A total of 100 protocols were analysed. Thirty-three and sixty-seven protocols were registered in the first and second time periods, respectively. An association between period and the timing of registration (prospectively or retrospectively) (P < 0.001) and funding source (University or Company) (P < 0.001) was evident. Overall, 25 of the 33 (75.5%) SPIRIT statement items were not reported in either timeframe. The median percent reporting quality score was 26.9 (IQR 6.9). The type of registry was associated with percent scores and published studies received better percent scores compared to unpublished studies and academic or private protocol submissions. CONCLUSIONS: There is a general lack of awareness of the importance and relevance of the SPIRIT statement. Registration of orthodontic trial protocols has apparently improved; however, 75.5% SPIRIT statement items were not reported in either study time period. The registration and reporting of orthodontic trial protocols should be advocated to circumvent issues relating to selective reporting and outcome reporting bias.

Extent and prevalence of spin in randomized controlled trials in dentistry.

OBJECTIVE: Spin, the misinterpretation of non-significant study results, can lead to erroneous conclusions about the effectiveness of interventions. It was the aim of this study to examine the presence and prevalence of spin in the dental literature and to identify potential associations with trials' characteristics. METHODS: PubMed was searched for randomized controlled trials (RCTs) published between February 12,018 and January 31, 2019. Two reviewers screened the selected articles and evaluated them for spin using a standardized data collection form. Data on the selected RCTs and spin strategy, if present, were recorded for each study. Descriptive statistics and frequencies of various types of spin in the abstract and the main text were calculated and associations between spin and study characteristics were examined. RESULTS: Forty-seven RCTs were included in the final sample. Over 60 % of the articles presented some form of spin and 19.1 % presented more than one types of spin in the abstract. More than one types of spin were detected in more than half of the studies evaluated (53.2 %), whereas 78.7 % of the studies screened presented some type of spin in the main text. No statistically significant associations were found between any of the study characteristics and spin or recommendations. There was a discrepancy in the presence of spin between abstracts and in the main text (p = 0.006). CONCLUSION: Dental RCTs' are not immune to misleading interpretation and both authors and readers should report and evaluate trial results based on the data at hand without unfounded extrapolations. CLINICAL SIGNIFICANCE: Spin, the conscious or subconscious misinterpretation of non-significant study results, can be misleading when applying trials' results in everyday clinical practice. Thus, researchers should abstain from including it in their trials and readers should identify it when evaluating a study.

The use of Bjork's indications of growth for evaluation of extremes of skeletal morphology.

BACKROUND: Morphological indicators within the cranium for prediction of mandibular growth patterns as reported by Bjork are: (1) inclination of the condylar head (ICH), (2) curvature of mandibular canal (CMC), (3) shape of the lower border of the mandible and specifically depth of the antegonial notch (AN), (4) inclination of the symphysis (ISY), (5) interincisal angle (IIA), (6) intermolar angle (IMA), and (7) lower anterior face height (LAFH). The purpose of this study was to examine the association of these indicators as they relate to extreme skeletal patterns observed in skeletally mature subjects. MATERIALS: The pre-treatment lateral cephalometric radiographs of 395 post-growth subjects were randomly selected from the archives of a university orthodontic department. These were divided in three groups according to their MP-SN angle [normal: 28-36degrees (G1), hypodivergent: ≤26degrees (G2), hyperdivergent: ≥38degrees (G3)]. RESULTS: It was found that only LAFH was correlated to age across all groups. However, within G1, G2, and G3, and between genders, it was found that there were statistically significant differences for all indicators in relation to age, except IMA (P > 0.05). In addition, ISY and IMA had a predictive value lower than the chance level (0.5). CONCLUSION: Bjork's implant studies have contributed much to understanding facial-skeletal growth; however, this study suggests that their utilization as a tool in classifying extreme skeletal patterns requires careful evaluation of all the parameters involved.

Osteogenic activity of ß-tricalcium phosphate in a hydroxyl sulphate matrix and demineralized bone matrix: a histological study in rabbit mandible.

Currently, in oral and maxillofacial surgery, there is a clinical need for efficient bone grafting materials, and various efforts are being made to improve materials used as bone substitutes to facilitate faster and denser bone regeneration. The purpose of this study was to evaluate in vivo the osteogenic potential of synthetic ß-tricalcium phosphate in a hydroxyl sulphate matrix (ß-TCP/HS) and human demineralized bone matrix (DBM) putty. Sixteen New Zealand White rabbits were used. In each animal, two bone defects (8 mm length × 3 mm width × 3 mm depth) were created in the left and right regions of the mandible, respectively. The defect on one side, chosen randomly, was filled with ß-TCP/HS (group A) or DBM putty (group B), while the defect on the opposite side was left unfilled in order to serve as a control site. Two animals in each group were sacrificed at the end of the 1st, 3rd, 5th and 6th week after surgery, respectively, and the osteotomy sites were processed for histological evaluation. Our findings confirmed that ß-TCP/HS and human DBM putty possess osteogenic activity and can support new bone formation, although at a slower rate than the spontaneous healing response, in rabbit mandibular osseous defects.