Image analysis of time-lapse movies--a precision control guided approach to correct motion artefacts

In long-term time-lapse studies of cell migration, it is often important to distinguish active movement of individual cells from global tissue motion caused, for instance, by morphogenetic changes, or due to artefacts. We have developed a method to define and correct global movements. This is realized by the sequential morphing of image sequences to the initial image based on the position of immobile reference objects. Technically, the approach is implemented in ImageJ, using the plugin UnwarpJ. We describe an efficient way to select parameter settings such as to optimize image correction. To this end, we implemented a strict statistical control that allows to quantify image registration quality. We document this approach using a time-lapse sequence of migrating interneurons in slice cultures of the developing cerebellum.     

The microstructure of peripheral nerves

An understanding of the normal peripheral nerve and its associated structures illuminates the events following a peripheral nerve injury. There are two overlapping stages: Wallerian degeneration followed by regeneration (Figure 10). Ideally, treatment interventions should be initiated early and take into account both of these phenomena. Although the physician cannot control the “biological battlefield” raging inside a damaged nerve, realistic goals according to Hall include: (1) therapy to keep more neurons alive; (2) encourage axons to cross longer interstump gaps; (3) maximize the accuracy of target reinnervation; and (4) manage the neuropathic pain.⁷     

External Cervical Resorption: A Volumetric Analysis on Evolution of Defects over Time

IntroductionThe aim of this study was to assess the temporal evolution of external cervical resorption (ECR) defects using a volumetric quantification method.MethodsCone-beam computed tomographic (CBCT) images of patients diagnosed with ECR who chose not to receive treatment and attended recalls were collected. ECR defects were segmented in CBCT images at baseline and recall, and their volumes were quantified. The volumetric ratio of resorption defects/teeth was calculated. Three-dimensional classification of defects at baseline and recall and the prevalence of root surface perforations ≥1 mm were determined. The Wilcoxon matched pairs signed rank test, chi-square test, and linear regression models were used to analyze the data.ResultsFifteen patients with 20 teeth diagnosed with ECR and an average recall time of 21 months were included. Nine (45%) teeth showed a change in 3-dimensional classification at recall. The volume of resorption defects (P = .0001) and the volumetric ratio of resorption defects/teeth (P = .0001) increased over time. The prevalence of root surface perforations ≥1 mm was higher at recall (n = 17, 85%) compared with baseline (n = 9, 45%) (P = .008). Linear regression models showed significant associations between the resorption defect volume at recall compared with baseline (P < .0001; 95% confidence interval, 0.053–0.081) and the volumetric ratio of resorption defects/teeth at recall compared with baseline (P < .0001; 95% confidence interval, 0.205-0.356). There was no association between the volume of resorption defects at recall with the length of the recall period, sex, or age (P > .05).ConclusionsWhen left untreated, ECR defects can increase in size and develop more root surface perforations. ECR has a dynamic nature, and its volumetric increase over time does not result from uniform/linear expansion of the defects.     

Risk Factors for and Clinical Presentations Indicative of Vertical Root Fracture in Endodontically Treated Teeth: A Systematic Review and Meta-analysis

IntroductionThe aim of this study was to identify specific clinical signs or symptoms and potential risk factors which are most likely associated with the presence of a vertical root fracture (VRF) in endodontically treated teeth (ETT).MethodsElectronic databases (MEDLINE via PubMed, EMBASE via Ovid, Scopus, and Web of Science) were searched by 2 reviewers in October 2022 for clinical studies, in which at least either the clinical presentation or potential risk factors associated with a VRF were assessed. Risk of bias was assessed using the Newcastle-Ottawa scale. Meta-analyses of odds ratios (ORs) were performed separately for several signs or symptoms and risk factors.ResultsFourteen sources reporting on 2877 teeth (489 with VRF and 2388 without VRF) were included in the meta-analyses. Regarding the clinical presentation, the presence of sinus tracts (OR = 4.87; 95% confidence interval [CI], 1.58–15.0), increased periodontal probing depths (OR = 13.24; 95% CI, 5.44–32.22), swelling/abscess (OR = 2.86; 95% CI, 1.74–4.70), and tenderness to percussion (OR = 1.76; 95% CI, 1.18–2.61) were significantly associated with the presence of a VRF (P_adj. value < .05). None of the assessed risk factors (sex, type of teeth, tooth location, posts, indirect restoration, and apical extension of the root canal filling) were found to be significantly associated with the presence of a VRF (P_adj. value > .05).ConclusionsFour clinical presentations were identified to be the most significant signs or symptoms for a VRF in ETT: presence of sinus tracts, increased probing depths, swelling/abscess, and tenderness to percussion. None of the assessed risk factors pointed out to be significantly associated with a VRF. Registration: CRD42022354108 (PROSPERO).     

Rare variant of dens invaginatus with accessory root and labial talon cusp in maxillary lateral incisor—Case report

Dens invaginatus (DI) often causes dysmorphic changes in both the crown and root. This case report presents a complicated type 3a DI in a maxillary lateral incisor with labial talon cusp and root bifurcation. Although lingual talon cusp is common in maxillary lateral incisor, labial talon cusp is rare. An auxiliary palatal root in maxillary lateral incisor is also unusual. No such case involving all three variations has been described in the literature. The DI was classified as type B4 according to Schulze and Brand, as it involved division of pulp and root. DI was managed by orthograde MTA, radisectomy and periodontal regeneration was done for the palatal root. Labial talon associated with DI and can lead to early periodontal/pulpal involvement. Type 3 DI can affect the root with marked dilatation and division. Additional palatal root should be carefully detected in type 3a DI and managed with the aid of CBCT.     

Influence of access cavity design,sodium hypochlorite formulation and XP-endo Shaper usage on apical debris extrusion – A laboratory investigation

This study assessed the amount of apically extruded debris during root canal preparation using XP-endo shaper and the supplemental use of XP-endo finisher comparing the use of traditional endodontic access or conservative endodontic access cavities and liquid or gel-based formulations of 5.25% sodium hypochlorite or distilled water as supplemental agents. Maxillary first premolar teeth (N = 148) were randomly divided based on their access cavity design and sub-grouped according to the supplemental agent used. The amount of extruded debris was analysed based on the dry weight of the debris collected using a previously established laboratory methodology. Debris extrusion occurred in all groups. Overall, the traditional endodontic access cavity design was associated with more debris extrusion compared to the conservative type. The use of sodium hypochlorite solution showed higher debris extrusion than the gel, whilst distilled water had intermediate values.     

The effects of adjunctive use of a desiccant agent in the treatment of stage III periodontitis (Randomized controlled clinical trial)

IntroductionSeveral bacterial species inhabiting the dental plaque biofilms are associated with periodontitis.ObjectiveThe main objective of this study was to compare the efficacy of the desiccant agent HYBENX (HBX) as an adjunct to scaling and root planning (SRPX) versus scaling and root planning (SRP) alone in the treatment of periodontitis.Materials and MethodsThe study sample comprised 25 patients with periodontitis stage Ш (grades A and B). Each maxillary quadrant was randomly allocated to two groups: SRPX group, including 25 quadrants treated with SRP plus HYBENX, and SRP group, including 25 quadrants treated with SRP alone. The following clinical periodontal parameters were recorded at baseline (immediately after treatment, T0), and 1 month (T1), 3 months (T3), and 6 months (T6) after treatment: probing pocket depth (PPD), relative attachment level (RAL), plaque index (PLI), gingival index (GI), gingival height (GH), and bleeding on probing index (BOP).ResultsComparisons within each study group showed that all clinical parameters significantly improved (P < 0.001) at all follow-up intervals. In contrast, a statistically significant difference (P < 0.001) was observed in RAL, PPD, BOP, and GI indices at all follow-up intervals between the SRPX and SRP groups. In contrast, no significant differences (P > 0.05) were found in GH and PLI between the study groups.ConclusionBoth treatment groups showed improved periodontal parameters. However, applying desiccant gel as an adjunct to SRP was significantly effective in the treatment of stage III periodontitis.     

Cryosections of pre-irradiated adult rat spinal cord tissue support axonal regeneration in vitro

Neonatal X-irradiation of central nervous system (CNS) tissue markedly reduces the glial population in the irradiated area. Previous in vivo studies have demonstrated regenerative success of adult dorsal root ganglion (DRG) neurons into the neonatally-irradiated spinal cord. The present study was undertaken to determine whether these results could be replicated in an in vitro environment. The lumbosacral spinal cord of anaesthetised Wistar rat pups, aged between 1 and 5 days, was subjected to a single dose (40 Gray) of X-irradiation. A sham-irradiated group acted as controls. Rats were allowed to reach adulthood before being killed. Their lumbosacral spinal cords were dissected out and processed for sectioning in a cryostat. Cryosections (10 μm-thick) of the spinal cord tissue were picked up on sterile glass coverslips and used as substrates for culturing dissociated adult DRG neurons. After an appropriate incubation period, cultures were fixed in 2% paraformaldehyde and immunolabelled to visualise both the spinal cord substrate using anti-glial fibrillary acidic protein (GFAP) and the growing DRG neurons using anti-growth associated protein (GAP-43). Successful growth of DRG neurites was observed on irradiated, but not on non-irradiated, sections of spinal cord. Thus, neonatal X-irradiation of spinal cord tissue appears to alter its environment such that it can later support, rather than inhibit, axonal regeneration. It is suggested that this alteration may be due, at least in part, to depletion in the number of and/or a change in the characteristics of the glial cells.