Table 3 Qualitative and categorical analysis of included publications where spin bias was detected
Author, year, country | Quoted text | Categories of spin accordingly Lazarus et al. [30] | Spin Analysis |
|---|---|---|---|
Al-Wayli 2017 [20] | Results in the abstract “Mean pain score due to Bruxism events in the masseter muscle decreased significantly in the botulinum toxin injection group A (P = 0.000, highly significant).” | 2 K, 3 M | The study did not evaluate bruxism events. Then the conclusion is not supported by the results In the main text, the statistical analysis did not evaluate the changes in both the control and the BTX-A group, only compared the difference between both groups. In the abstract, on the other hand, the authors inform the before and after results for each group and not the comparison between them The results did not show that the reapplication is necessary because the patients were not reevaluated after 15 days and there is no information on reapplication. Also, according to the results the improvement in the pain was stable in 6 months and one year The authors use linguistic spin (“highly significant”) to emphasize the results |
Conclusion in the abstract “Our results suggest that BTX injection reduced the mean pain score and number of bruxism events, most likely by decreasing the muscle activity of masseter rather than affecting the central nervous system.” | 2 J, 3 M, 3O | ||
Results in the main text “There was highly significant difference in mean pain score post-operatively at 3 weeks in group I and group II (p = 0.000). The mean pain score at 2nd month post-operatively in group I was 2.5 ± 0.59 and in group II was 4.3 ± 0.48. There was highly significant difference in mean pain score at post-operative 2nd month in group I and group II.” | 1D, 2 K, 2 J, 3 M, 3O | ||
Conclusion in the main text “20 UI per side BTX injection in the masseter muscles is an effective and safe means of intervention in cases of moderate to severe chronic myofascial and TMJ pain associated with bruxism. The patient should be evaluated 15 days after the application and return for control after three or four months after the application for a new evaluation and another application, if needed.” | 3 M, 3N | ||
Alwayli et al. 2024 [23] | Results in the abstract “The study included 24 females and 16 males aged 21 to 52 years (mean 33.9 ± 31.0). The mean VPS score on the first day was 5.75 (± 1.9), significantly decreasing after two weeks to 0.44 (± 0.727). The mean difference of VPS from 8 weeks up to 24 weeks gradually increase from 0.69 at 8 weeks to 2.00 at 24 weeks.” | 1B, 2G | The results are not clearly reported. The outcomes are described as “Pain at rest and chewing, assessed by using a VPS from 0 to 10, with the extremes being no pain and pain as bad as the patient has ever experienced, assessed at baseline and follow-up appointments, i.e., at 2 weeks, 4, 8, 12, 16, 18, 20, and 24 weeks.” However, in the results the authors have presented two different measurements. The first one is “the mean subjective VPS”. For this outcome, only results from the BTX-A group were reported at 2 weeks, 4, 8, 12, 16, 18, 20, and 24 weeks. The second is “the mean pain score”. For this one, the authors have presented the results for both groups only at 2, 8 and 24 weeks. Also, it is important to highlight that the results from the control group can be correct, but they are exactly the same in the three follow-up points Besides that, the BTX-A was evaluated alone, then, cannot be considered “a useful adjunct” treatment So, we considered that this study has selective reporting, claims of significant difference despite lack of statistical test and the conclusion cannot not be supported by the results. Also, the authors use linguistic spin (“highly significant”) to emphasize the results |
Conclusion in the abstract “This study provides evidence that BTX-A could reduce the pain of nocturnal bruxism in affected patients.” | 1B, 3 M, 3N | ||
Results in the main text “This study shows that BTX-A could reduce the pain of nocturnal bruxism in affected patients. The VPS scores showed significant decrease of pain initially. Very mild pain returned after 12 weeks; however, tolerability and subjective efficacy of treatment were rated by most as either good or excellent.” | 1B, 2G, 2 J, 3 M | ||
Conclusion in the main text “It can be concluded that injectable BTX-A is a useful adjunct in the management of bruxism.” | 1D, 3 M, 3N | ||
Jadhao et al. 2017 [21] | Results in the abstract No spin | - | The results of the statistical analysis for “Duration of clenching and releasing” are not presented anywhere in the main text “To determine the precision of the occlusal analysis system” was not described as a purpose of the study. Therefore, the conclusion should not consider this variable The authors use linguistic spin (“obvious advantages”) in the conclusion |
Conclusion in the abstract No spin | - | ||
Results in the main text No spin | - | ||
Conclusion in the main text “We also achieve that the occlusal analysis system precisely imitates the characteristics of occlusal force during treatment of bruxism.” “BTX‑A has obvious advantages for the treatment of bruxism in terms of tumbling the occlusal force.” | 1D, 3 M, 3O | ||
Lee et al. 2010 [22] | Results in the abstract No spin | - | The results for this study were positive only for masseter muscle, not for temporalis So, we considered that this study has selective reporting, claimed an effect for non-statistically significant results (temporalis) and the conclusion cannot not be supported by the results. Therefore, we considered a spin interpreting statistically nonsignificant results of the temporalis muscle as showing treatment equivalence or comparable effectiveness |
Conclusion in the abstract “Our results suggest that BTX injection reduced the number of bruxism events, most likely mediated its effect through a decrease in muscle activity rather than the central nervous system.” | 1B | ||
Results in the main text No spin | - | ||
Conclusion in the main text “Our results showed that the injection of BTX in the masseter muscle reduced the number of bruxism events during sleep, most likely mediated through its effect on muscle tone rather than central nervous system. BTX injection can be used as an effective treatment for nocturnal bruxism.” | 1B, 2G, 3 M, 3N | ||
Ondo et al. 2018 [24] | Results in the abstract “CGI (p < 0.05) and VAS of change (p < 0.05) favored the BTX-A group. None of the exploratory endpoints changed significantly, but total sleep time and number/duration of bruxing episodes favored the BTX-A group. Two participants randomized to BTX-A reported a cosmetic change in their smile. No dysphagia or masticatory adverse events were reported.” | 1B | There is selective reporting in the abstract, because the results did not report the number of bruxism events in both groups The results for pain and bruxism (assessed by VAS) were not described and they were only presented in “Table 1—Demographics and efficacy points” Also, the results for Bruxism Quest score, which shows that there was no difference in the changes from baseline to four weeks between both groups (p = 0.11), were not described in the text We also considered that the study did not evaluate efficacy, presented a selective reporting and claimed for a significant difference despite the lack of statistical test. Moreover, inadequate extrapolation and inadequate implication for clinical practice were also detected |
Conclusion in the abstract “BTX-A effectively and safely improved sleep bruxism in this placebo-controlled pilot trial.” | 3 M, 3N | ||
Results in the main text Table 1 Demographics and efficacy points | , 2 K | ||
Conclusion in the main text Not described in the main text | 3 M, 3N | ||
Shehri et al. 2022 [25] | Results in the abstract No spin Conclusion in the abstract No spin Results in the main text Table 2 (no comparison between different follow up points and the baseline – the statistically significant difference may be misleading) Conclusion in the main text No spin | 3O | Table 2 presents comparisons for each evaluation time with the previous one. The existence of statistical significance from 3 months onward means a worsening of the condition, but since there is no comparison with the baseline, it is difficult to interpret and may be misleading to the reader |
Shim et al. 2020 [26] | Results in the abstract No spin | - | The authors state that the study evaluated “long-term effect” when 3 months is the usual duration of the botulinum toxin The study did not evaluate occlusal splints and therefore, this conclusion was not supported by the results |
Conclusion in the abstract “The injection decreased the peak amplitude of EMG bursts during SB only in the treatment group for 12 weeks (p < 0.0001). A single BTX‐A injection cannot reduce the genesis of SB. However, it can be an effective management option for SB by reducing the intensity of the masseter muscle.” | 3 M, 3N | ||
Results in the main text No spin | - | ||
Conclusion in the main text “This study is significant for evaluating the long‐term effect of BTX‐A for SB using PSG evaluation in a randomized, placebo‐controlled trial.” “Changing the concept of SB, i.e., from disorder to behavior, we can use BTX-A as an effective modality in reducing the intensity of masticatory muscle during SB along with occlusal splints. In the future, we need randomized, double-blind, placebo-controlled clinical studies with an accurate SB diagnosis by several consecutive PSG recordings and large sample size.” | 1D, 3 M, 3N, 3O | ||
Yurttutan et al. 2019 [27] | Results in the abstract No spin | - | In the main text, the conclusion is not clear. In fact, the results showed that the combined therapy is more effective in comparison to the other treatments. However, the authors concluded that the BTX therapy and combined occlusal splint and BTX therapy were more effective Thus, we considered that the authors claimed equivalence for non-statistically significant results, and there is an inadequate interpretation of the results and, consequently, inadequate implications for clinical practice |
Conclusion in the abstract “Occlusal splints might not be necessary for patients treated with botulinum toxin injections.” | 3 M, 3N | ||
Results in the main text No spin | - | ||
Conclusion in the main text “According to our findings, the use of an occlusal splint will benefit patients.” although BTX therapy and combined occlusal splint and BTX therapy were more effective. BTX therapy effectively improved myofascial pain with or without the use of an occlusal splint.” | 3 M, 3N |