Influence of the Gingival Condition on the Performance of Different Gingival Displacement Methods—A Randomized Clinical Study

This randomized clinical study examined the influence of the gingival condition—healthy versus mild inflammation—on sulcus representation and possible gingival recession for two gingival displacement procedures prior to conventional impression making. The interventions double cord technique or a kaolin paste containing aluminum chloride were applied to 40 probands. The opposite quadrant served as intrapersonal reference (split-mouth design). Precision impressions were then made. Extraoral digitization of the plaster models resulting from the reference impression prior to gingival displacement, the intervention impression and control impressions were the basis for the computer-aided three-dimensional analysis. After six months, a mild artificial gingivitis was induced, and the contralateral quadrant (cross-over design) was examined for the intervention. The gingivitis deteriorated the sulcus representation for the double cord technique group but did not affect the paste technique group. The gingival condition had no influence on the marginal gingiva height changes. The minor extent of those changes, which were measured up to six months after intervention at the palatal study site, were not considered to be in the clinically relevant range for gingival recession. For healthy gingiva, the cord technique showed superior sulcus representation compared to the paste technique. This advantage was lost to a great extent under the conditions of mild gingivitis.

Evaluating the Influence of Conspecifics on a Male Giant Anteater's (Myrmecophaga tridactyla) Pacing Behavior

Stereotypic behavior has been studied in various species, but little information exists on stereotypies in giant anteaters (Myrmecophaga tridactyla) under professional care. Giant anteaters are known for their solitary nature and well-developed sense of smell. This study examined the effect of conspecifics who were housed off-exhibit on a male giant anteater’s rate of pacing and pacing intensity when he was on-exhibit. Instantaneous sampling was used to determine the percentage of time pacing, the number of pacing bouts and pacing bout duration. Randomization tests determined that the reduction in the male giant anteater’s rate of pacing significantly decreased after conspecifics were relocated to a different building. Pacing bout duration, a potential measure of intensity, also significantly decreased during the treatment phase. In addition, the giant anteater changed his pacing location after the removal of conspecifics. He transitioned from pacing near the conspecifics’ off-exhibit location during the baseline to the opposite quadrant of the exhibit after their departure. These results suggest that keeping a male giant anteater in proximity to conspecifics without the ability to interact with them had an impact on his behavior. Better understanding the motivations for stereotypic behaviors of giant anteaters will better inform housing decisions made by zoo professionals.

Reversal learning paradigm reveals deficits in cognitive flexibility in the Fmr1 knockout male mouse

Background: Loss of FMR1 is associated with Fragile X syndrome, amongst the most prevalent inherited intellectual disability. Despite extensive research in this area, previous studies have failed to detect consistent evidence of cognitive impairments in the Morris water maze (MWM) task in the Fmr1 knockout (KO) mouse. However, few studies have examined cognitive flexibility in a reversal form of the MWM task, which may illuminate subtle learning deficits. Methods: Adult male Fmr1 wildtype (WT) and KO mice were bred and tested in the MWM reversal paradigm. The testing paradigm consisted of two blocks per day, with 4 trials per block to locate a hidden platform. After the last trials on the fourth day of testing, the animals were given a probe trial with the platform removed. The following week, the location of the platform was switched to the opposite quadrant and the animals received 2 more days of testing, with 4 blocks in total. Results: As expected, Fmr1 KO mice did not display a learning deficit during the acquisition phase, Fgenotype (1, 24) = 0.034, p = 0.854, and performed similarly on the probe trial, Fgenotype (1, 23) = 0.024, p = 0.877. However, during the reversal phase of learning, Fmr1 KO mice showed deficits in their ability to learn the new location of the platform, Fgenotype (1, 23) = 3.93, p = 0.059. Further independent samples t-testing revealed that KO animals displayed significantly higher latency to reach the hidden platform during the third trial, t(23) = -2.96, p < 0.01. Conclusions: While previous studies have not demonstrated deficits in spatial memory in the Fmr1 KO model, it is possible that the acquisition phase of the task is less sensitive to deficits in learning. Future studies using this model to evaluate therapeutic interventions should consider utilizing the MWM reversal paradigm.