Tuned geometries of hippocampal representations meet the computational demands of social memory.

Social memory consists of two processes: the detection of familiar compared with novel conspecifics and the detailed recollection of past social episodes. We investigated the neural bases for these processes using calcium imaging of dorsal CA2 hippocampal pyramidal neurons, known to be important for social memory, during social/spatial encounters with novel conspecifics and familiar littermates. Whereas novel individuals were represented in a low-dimensional geometry that allows for generalization of social identity across different spatial locations and of location across different identities, littermates were represented in a higher-dimensional geometry that supports high-capacity memory storage. Moreover, familiarity was represented in an abstract format, independent of individual identity. The degree to which familiarity increased the dimensionality of CA2 representations for individual mice predicted their performance in a social novelty recognition memory test. Thus, by tuning the geometry of structured neural activity, CA2 is able to meet the demands of distinct social memory processes.

Effectiveness of metronidazole gel and mobile telephone short-message service reminders on gingivitis in orthodontic patients.

OBJECTIVES: To compare the effectiveness of metronidazole gel and mobile telephone short-message service (SMS) reminders on gingivitis in patients undergoing fixed orthodontic treatment. MATERIALS AND METHODS: The trial was double blinded (patient and investigator), and only the clinical trial unit pharmacist was unblinded. Data were collected from patients undergoing fixed orthodontic treatment for at least 6 months. A total of 66 patients were randomly assigned to either 0.8% metronidazole gel (n = 22), SMS reminder and placebo gel (n = 22), or placebo (control) group only (n = 22). Gingival index (GI), bleeding index (BI), and orthodontic plaque index (OPI) were evaluated on several teeth at baseline (T0) and after 4 weeks (T1). Paired-sample t-tests were used to compare mean differences of indexes at T0 and T1 in the groups, and independent-sample t-tests were used to determine the effects of interventions compared with the controls. RESULTS: Data from 64 patients were analyzed; there were 2 dropouts. There were statistically significant (P < .05) reductions in GI, BI, and OPI scores from T0 to T1 for each intervention. However, there were no significant differences between each intervention and the control group. There were no adverse effects. CONCLUSIONS: The null hypothesis could not be rejected. There is no difference between interventions (application of 0.8% metronidazole gel and SMS reminder for reinforcing oral hygiene) in reducing gingival inflammation in orthodontic patients.

Comparison between conventional and piezocision-assisted orthodontics in relieving anterior crowding: a systematic review and meta-analysis.

BACKGROUND: Prolonged duration of orthodontic treatment is of great concern and poses risks to the teeth and surrounding tissues. Orthodontic tooth movement can be accelerated by introducing regional insult. Evidence suggests piezocision to be minimally invasive and clinically effective. OBJECTIVE: The aim of the present study was to compare the effectiveness of conventional and piezocision-assisted orthodontics in relieving anterior crowding. SEARCH METHODS: Electronic and manual searches were conducted in databases including PubMed, Dental and Oral Science, CINAHL, and Cochrane Central Register of Controlled Trials until April 2019. SELECTION CRITERIA: Randomized and non-randomized controlled trials were included. DATA COLLECTION AND ANALYSIS: Data were extracted independently by two authors from the studies that fulfilled inclusion criteria. The primary outcome assessed was time required for the alleviation of crowding. The secondary outcomes evaluated were pain, root resorption, and periodontal health. The risk of bias in the clinical trials was evaluated according to the Cochrane Collaboration's tool. Studies having homogenous data were included in the meta-analysis using the RevMan software. RESULTS: Initial search yielded 3018 studies with eight articles meeting the inclusion criteria, six were randomized controlled trials and two were non-randomized controlled trials. Significant differences were found in alignment time between conventional and piezocision-assisted orthodontic treatment. However, gingival health, pain experienced by the patient, and root resorption showed non-significant differences. The forest plot of meta-analysis depicted significant mean difference of -46.44; 95 per cent confidence interval (CI) -87.95, -4.93; P ≤ 0.03 in the alignment time. Difference in pain levels was found to be non-significant (P = 0.78). LIMITATIONS: There is a shortage of high-quality randomized controlled trials with a limited sample size and lack of standardization of piezocision protocol. CONCLUSIONS AND IMPLICATIONS: According to the existing evidence, piezocision is effective in reducing tooth alignment time and alleviating crowding when compared to conventional therapy. Pain levels showed insignificant differences revealed in meta-analysis. Weak evidence suggests that there are no negative effects on periodontal health and root resorption after performing piezocision. REGISTRATION: PROSPERO (CRD42019134398).

Comparison of anchorage loss between conventional and self-ligating brackets during canine retraction - A systematic review and meta-analysis.

INTRODUCTION: Anchorage is defined as the resistance to unwanted tooth movement. In orthodontics, loss of anchorage can be detrimental to treatment. The proponents of orthodontic self-ligating brackets (SLB) advocate the use of extremely light forces thereby reducing anchorage burden. Therefore, the aim of this study was to compare anchorage loss during canine retraction between conventional brackets (CB) and self-ligating brackets. METHODS: An electronic search was conducted on the Cochrane database, Scopus, Web of Science, PubMed, Dental & Oral Science and CINAHL, along with handsearching Google Scholar and clinicaltrials.gov. Randomized or non-randomized clinical trials published in the English language on human subjects were included. Orthodontic patients undergoing canine retraction after premolar extraction bonded with self-ligating brackets as the intervention and conventional brackets as the control group in a split mouth design were included. Primary outcome studied was anchorage loss; secondary outcomes were retraction velocity and total amount of canine retraction. Two researchers carried out data extraction and study selection independently. The risk of bias was calculated using the Cochrane's Risk of Bias Assessment tool. The RevMan software was used for quantitative synthesis of data. Effect estimate of the primary and secondary outcomes was expressed using weighted mean difference and 95% confidence intervals (CIs). Heterogeneity of the studies was evaluated using the Cochrane's test for heterogeneity (I2 Test); subgroup and sensitivity analyses were performed to investigate sources of heterogeneity among the studies. RESULTS: Results of the literature search across all databases yielded 10,439 hits, out of which five studies were included in the qualitative synthesis that met the inclusion criteria. Four studies were randomized control trials (RCTs) where as one was a non-randomized control trial, with 100 subjects included in this systematic review. All studies used a split mouth design. Of the five studies included, only one reported significant differences between CB and SLB for anchorage loss, retraction velocity and total amount of canine retraction (P-value≤0.001). Four studies were included in the meta-analysis, which showed no difference in the amount of anchorage between self-ligating and conventional brackets (weighted mean difference - 0.22; 95% CI [-0.82, 0.38]; P=0.48). Multiple subgroup analyses further revealed there were no significant differences between the intervention and control groups for all outcomes studied. CONCLUSION: This systematic review and meta-analysis found insufficient evidence to suggest a significant difference in anchorage loss between the CB and SLB groups. The scarcity of current evidence dictates that further studies are needed to canonically establish the clinical superiority of one over the other. REVIEW REGISTRATION: PROSPERO 2019 CRD42019133217.

Comparison of soft and hard tissue changes between symmetric and asymmetric extraction patterns in patients undergoing orthodontic extractions.

BACKGROUND: Orthodontic treatment modalities and biomechanics are important factors influencing soft and hard tissues. OBJECTIVES: The aim of this study was to compare soft and hard tissue changes after implementing asymmetric and symmetric extraction patterns. MATERIAL AND METHODS: A retrospective cross-sectional study was conducted using the orthodontic files of 62 patients from the dental clinics of a tertiary care hospital. Patients were divided into 2 groups, each of 31 patients. Group 1 referred to the symmetric extraction patterns (SEP), whereas group 2 regarded the asymmetric extraction patterns (AEP). The Wilcoxon signed-rank test was used to determine differences between the initial and final cephalometric parameters. The Mann-Whitney U-test was used to compare the treatment changes between SEP and AEP. The SEP and AEP groups were divided into subgroups for further analyses. The Kruskal-Wallis test was used to determine significant differences in the cephalometric changes among the different subgroups. In order to further establish inter-group differences, a pairwise comparison between the subgroups was made using the Mann-Whitney U-test. RESULTS: In the symmetric group, the preand post-treatment values for all soft tissue variables, upper incisor-sella-nasion plane angle (UI-SN), lower incisor mandibular plane angle (L-IMPA), and Frankfurtmandibular plane angle (FMA) showed significant differences (p ≤ 0.05). In the asymmetric group, none of the soft tissue parameters showed any significant difference in the preand post-treatment values; however, FMA and L-IMPA differed significantly (p ≤ 0.05). The parameters UI-SN and FMA as well as all soft tissue variables except Z-angle (Z), were significantly different between the SEP and AEP groups. The medians and interquartile ranges (IQRs) of the cephalometric changes among the subgroups were compared using the Kruskal-Wallis test. All soft tissues parameters except Z showed significant differences. CONCLUSIONS: The symmetric extraction patterns leads to a greater change in the patient's profile, whereas asymmetric extractions can be carried out to remedy occlusal discrepancies without the risk of profile flattening. While employing premolar extractions aiming to reduce the facial height, due consideration with respect to biomechanics must be given.

Contamination assessment of orthodontic bands after different pre-cleaning methods at a tertiary care hospital.

INTRODUCTION: Infection control in dentistry is a major concern due to risk of transmission of communicable diseases. The aim of this study is to evaluate and compare the efficacy of various pre-cleaning methods for the tried-in orthodontic bands. MATERIAL AND METHODS: An in-vitro experimental study was conducted at the Central Sterilization Services Department (Dental Clinic) and the Microbiology lab at our university hospital. A total of 130 bands were included in our study which comprised 10 controls and the rest were equally divided into three groups according to the pre-cleaning methods, i.e. manual scrubbing, enzymatic solution and a combination of both. The orthodontic bands were incubated in the brain heart infusion broth at 37 °C for five days after pre-cleaning and sterilisation in a steam autoclave and were assessed for any bacterial growth. The chi-square test was applied to determine any significant association between the various pre-cleaning methods and the frequency of bands that showed growth. Effect size was calculated using the phi coefficient. RESULTS: The enzyme method revealed 5% of the sample to exhibit bacterial growth, whereas manual scrubbing and the combination of both showed no growth. There was no statistically significant difference among the three methods (P = 0.131). Further investigations showed the presence of Staphylococcus non-aureus bacterial species in contaminated bands from group II. CONCLUSIONS: All pre-cleaning methods were found to be equally effective in the decontamination of bands. Hence, the tried-in bands can be safely reused after pre-cleaning and sterilisation.

Alexithymia Predicts Cognitive Deficits In Patients With Idiopathic Parkinson's Disease.

BACKGROUND: Most of the orthodontic cases require a long period of retention which is usually carried out with the help of fixed retainers (FR). One of the downsides of FR is that these are prone to breakages. The aim of the present study was to identify the frequency and factors associated with failure of fixed spiral wire retainers.. METHODS: A retrospective crosssectional study was conducted using orthodontic files and dental casts of 126 patients from dental clinics of a tertiary care hospital. Descriptive statistics were applied to calculate the frequency and most common site of breakages. Chi-square test was applied to compare the frequency of breakages among age groups and different retainer spans. Independent sample ttest was used to compare the mean overbite in retainer breakage and retainer intact groups. A p-value ≤0.05 was considered as statistically significant. RESULTS: The frequency of retainer breakage was found to be 53.1%. Maxillary retainer breakages were found in 41.3% subjects whereas mandibular retainer failed in 22.2% subjects. The mean survival time of retainer was 8.91±4.57 months. The detachment of the retainer from the tooth surface was the most common occurrence (86%). The most common site of retainer breakage was maxillary canine (32.5%) and mandibular central incisor (12.7%). All the subjects who had retainers extending till maxillary molars encountered breakages.. CONCLUSIONS: A longer retainer span is associated with a greater risk of breakage. Failure rate in the maxillary arch was higher than the mandibular arch. The most common sites were the maxillary canine and mandibular central incisor. The most common pattern was wire detachment.