## 4 Discussion
Although there is little data on the life-cycle of Altmetric resources, it seems realistic to expect that a published item will reach the end of its social media buzz-cycle within a year after publication [6]. To study the life cycle of Altmetric we designed this observational longitudinal study. To our best knowledge, this is the first study on the longitudinal behavior of altmetrics in the current dental and orthodontic literature at a global level. Unlike classic bibliometric indicators that only consider mentions (citations) and production (publications) of research outputs, altmetric indicators take into account a broader and more complex set of factors related to the usage, mentioning, sharing, and bookmarking of a published item. This broader analysis of research impact raises more theoretical concerns, since each indicator represents a distinct action that occurs at different times and in different settings [23]. In our sample, the increase in Tweets is anecdotical in most of the journals, being this finding in agreement with what was reported by other authors. [PERSON] in 2011 highlighted that most articles receive tweets within 60 days after publication [24]. [PERSON] in 2018 reported that in his sample Tweets display an abrupt increase during the first 90 days and then remain constant demonstrating a short half-life [25]. In our sample, Facebook posts follow the same behavior as Tweets and can be considered as early attention trackers. It should be considered that Facebook had, in the first trimester of 2022, 2.91 billion monthly active users, which represents for almost a third of the world population [26]. As reported by [PERSON] et al. in 2016, despite the large number of users, it seems that research outputs are not widely disseminated on Facebook. In their review, only 7.7% of published items were shared on Facebook, significantly less than the 59.2% reported for Mendeley users or the 24.3% for Twitter [27]. It should be emphasized that some social media, such as Twitter or Facebook, are censored or blocked in some key nations, such as China or Russia [28], which could affect the number of users who can actually use these socials and, consequently, the global data from which the AAS is calculated. Blogs display very slight fluctuation during the studied period, in agreement with what was reported by other authors who outlined how the life cycle of Blog mentions reaches its roof after 90 days (1.9%), showing the same rapid and short life cycle that tweets and Facebook posts [25]. [PERSON] et al. in 2014 reported that the vast majority of articles cited on a blog were published during the same year of publication [29]. In our sample News Outlets, Patents, and Policy sources appeared as the Altmetric resources that increased the most over time. [PERSON] et al. 2016 in agreement with our findings reported that policy sources were one of the slower resources to accumulate, in contrast to Tweets, Facebook posts, or Blogs which were early indicators of online attention [27]. In light of our results, it seems questionable to insert such items in the AAS calculation since they did not display the immediacy that Altmetric is supposed to have and that is a key distinguishing factor when compared to classic citations. Consistent with what [PERSON] proposed in 2020 the dissemination of a published item on Facebook, Twitter or mainstream media provides an overview of the influence on public opinion while the indicators such as patents or policy sources highlight the knowledge transfer from the researcher to society being possible indicators of societal impact [27]. According to our data when publications with Altmetric resources score equal to 0 are compared with those with a score greater than or equal to 1 in 2019, are compared for citations in WOS 2021, a statistically significant difference in citations is observed for most of the resources explored except Patents, a similar finding was reported by other authors in a different field of medicine [30].