Alexandra K. Papadopoulou

Load application induces changes in the expression levels of Sox‐9, FGFR‐3 and VEGF in condylar chondrocytes

Experimental and clinical observations have proven the modulatory effects of mechanical loading on the development and maintenance of cartilage architecture. Here we examined the involvement of Sox‐9, FGFR‐3 and VEGF (pivotal factors controlling cartilage development and growth) in the mechano‐transduction pathway of mandibular condylar cartilage by changing the dynamics of the transmitted load via changes in food hardness. To this end, condyle cartilage tissue of rats fed with hard or soft food was analyzed immunohistochemically at various time points. Our findings demonstrate that different mechanical loading conditions in condylar chondrocytes trigger differentiation‐/maturation‐related processes by affecting the expression levels of these factors, ultimately influencing condylar cartilage growth.

Impaction and apical root angulation of the maxillary central incisors due to supernumerary teeth: Combined surgical and orthodontic treatment

This case report describes the treatment of a boy with both central maxillary incisors impacted because of 2 supernumerary teeth. Therapeutic management of the impacted teeth was combined with orthodontic treatment of a Class II Division 1 malocclusion. A sequential approach of surgical removal of the supernumerary teeth with 2 stages of surgical exposure and orthodontic traction of the impacted teeth resulted in proper incisor positioning. Close monitoring and multidisciplinary cooperation during the various treatment phases led to a successful esthetic result, with good periodontal health and functional occlusion.

Corticotomies and Orthodontic Tooth Movement: A Systematic Review

PURPOSE A systematic review was conducted to examine the evidence for the effectiveness and safety of corticotomy-facilitated orthodontics. MATERIALS AND METHODS Electronic databases (Ovid Medline, EMBASE, Cochrane, SCOPUS, and Web of Science) were searched for articles that examined the rate of corticotomy-facilitated orthodontic tooth movement and its effects on the periodontium, root resorption, and tooth vitality. Unpublished literature was searched electronically through ClinicalTrials.gov (http://www.clinicaltrials.gov) and the ISRCTN registry (http://www.controlled-trials.com). Relevant orthodontic journals and reference lists also were checked for eligible studies. Randomized clinical trials (RCTs) and controlled clinical trials (CCTs) were considered. Two article reviewers independently assessed the search results, screened the relevant articles, performed data extraction, and evaluated the methodologic quality of the studies. RESULTS Fourteen eligible articles (6 RCTs and 8 CCTs) were included in the review. There was a statistically meaningful increase in the rate of tooth movement compared with controls for all corticotomy techniques assessed. Some studies reported that acceleration in tooth movement was only temporary (lasting a few months). Corticotomy procedures did not seem to produce unwanted adverse effects on the periodontium, root resorption, and tooth vitality. The quality of the body of evidence was regarded as low owing to the presence of multiple methodologic issues, high risks of bias, and heterogeneity in the included articles. CONCLUSION Corticotomy procedures can produce statistically and clinically meaningful temporary increases in the rate of orthodontic tooth movement with minimal side-effects. Additional high-quality randomized clinical trials are needed to allow more definitive conclusions.

Effect of piezocision on root resorption associated with orthodontic force: A microcomputed tomography study

Introduction The purpose of this study was to investigate the effect of piezocision on orthodontically induced inflammatory root resorption. Methods Fourteen patients were included in this split‐mouth study; 1 side was assigned to piezocision, and the other side served as the control. Vertical corticotomy cuts of 4 to 5 mm in length were performed on either side of each piezocision premolar, and 150‐g buccal tipping forces were applied to the premolars. After 4 weeks, the maxillary first premolars were extracted and scanned with microcomputed tomography. Results There was a significantly greater total amount of root resorption seen on the piezocision sides when compared with the control sides (P = 0.029). The piezocision procedure resulted in a 44% average increase in root resorption. In 5 patients, there was noticeable piezocision‐related iatrogenic root damage. When that was combined with the orthodontic root resorption found on the piezocision‐treated teeth, there was a statistically significant 110% average increase in volumetric root loss when compared with the control side (P = 0.005). Conclusions The piezocision procedure that initiates the regional acceleratory phenomenon may increase the iatrogenic root resorption when used in conjunction with orthodontic forces. Piezocision applied close to the roots may cause iatrogenic damage to the neighboring roots and should be used carefully. HighlightsPiezocision might cause increased root resorption when used with orthodontic forces.Piezocision‐related iatrogenic root damage occurred in 5 of 14 participants.Piezocision should not be used in areas of close root proximity.

Role of Cathepsin S in Periodontal Inflammation and Infection

Cathepsin S is a cysteine protease and regulator of autophagy with possible involvement in periodontitis. The objective of this study was to investigate whether cathepsin S is involved in the pathogenesis of periodontal diseases. Human periodontal fibroblasts were cultured under inflammatory and infectious conditions elicited by interleukin-1β and Fusobacterium nucleatum, respectively. An array-based approach was used to analyze differential expression of autophagy-associated genes. Cathepsin S was upregulated most strongly and thus further studied in vitro at gene and protein levels. In vivo, gingival tissue biopsies from rats with ligature-induced periodontitis and from periodontitis patients were also analyzed at transcriptional and protein levels. Multiple gene expression changes due to interleukin-1β and F. nucleatum were observed in vitro. Both stimulants caused a significant cathepsin S upregulation. A significantly elevated cathepsin S expression in gingival biopsies from rats with experimental periodontitis was found in vivo, as compared to that from control. Gingival biopsies from periodontitis patients showed a significantly higher cathepsin S expression than those from healthy gingiva. Our findings provide original evidence that cathepsin S is increased in periodontal cells and tissues under inflammatory and infectious conditions, suggesting a critical role of this autophagy-associated molecule in the pathogenesis of periodontitis.

Volumetric upper airway changes after rapid maxillary expansion: a systematic review and meta-analysis

Background Although Rapid Maxillary Expansion (RME) has been used for over a century, its effect on upper airways has not yet adequately been assessed in an evidence-based manner. Objective To investigate the volumetric changes in the upper airway spaces following RME in growing subjects by means of acoustic rhinometry, three-dimensional radiography and digital photogrammetry. Search methods Literature search of electronic databases and additional manual searches up to February 2016. Selection criteria Randomized clinical trials, prospective or retrospective controlled clinical trials and cohort clinical studies of at least eight patients, where the RME appliance was left in place for retention, and a maximum follow-up of 8 months post-expansion. Data collection and analysis After duplicate data extraction and assessment of the risk of bias, the mean differences and 95 per cent confidence intervals (CIs) of upper airway volume changes were calculated with random-effects meta-analyses, followed by subgroup analyses, meta-regressions, and sensitivity analyses. Results Twenty studies were eligible for qualitative synthesis, of which 17 (3 controlled clinical studies and 14 cohort studies) were used in quantitative analysis. As far as total airway volume is concerned patients treated with RME showed a significant increase post-expansion (5 studies; increase from baseline: 1218.3mm3; 95 per cent CI: 702.0 to 1734.6mm3), which did not seem to considerably diminish after the retention period (11 studies; increase from baseline: 1143.9mm3; 95 per cent CI: 696.9 to 1590.9mm3). Limitations However, the overall quality of evidence was judged as very low, due to methodological limitations of the included studies, absence of untreated control groups, and inconsistency among studies. Conclusions RME seems to be associated with an increase in the nasal cavity volume in the short and in the long term. However, additional well-conducted prospective controlled clinical studies are needed to confirm the present findings. Registration None. Funding Australian Society of Orthodontics Foundation for Research and Education Inc.

The effect of low-level laser therapy on orthodontically induced root resorption: a pilot double blind randomized controlled trial

Background The effect of low-level laser therapy (LLLT) on accelerating orthodontic tooth movement has been extensively studied; however, there is limited knowledge on the use of LLLT on orthodontic root resorption. Objective To investigate the effect of LLLT on orthodontically induced inflammatory root resorption (OIIRR) and to compare the difference between pulsed and continuous LLLT on OIIRR. Trial design Double-blind, single-centre 3-arm parallel split-mouth randomized controlled trial. Participants Twenty adolescent patients who required bilateral maxillary first premolar (MFP) orthodontic extractions were recruited from the Sydney Dental Hospital between October 2014 and December 2014. Intervention All MFPs were tipped buccally for 28 days to induce OIIRR. The experimental premolars (n = 20) received LLLT and the control premolars (n = 20) received placebo-laser on days 0, 1, 2, 3, 7, 14, and 21. Ten experimental premolars received LLLT via continuous delivery and 10 received pulsed delivery. Laser parameter AlGaAs diode laser of 808 nm wavelength, 0.18 W power, 1.6 J per point, and duration of 9s for continuous mode and 4.5 s for pulsed mode. Outcome The difference in root resorption crater volume between LLLT and placebo-laser and continuous or pulsed laser delivery after 28 days. Randomization Randomization was computer-generated, with allocation concealment by opaque sequentially numbered sealed envelopes. Blinding The participants and operator were blinded. Results Eighty-eight patients were screened and 20 patients were randomized. Forty premolars were analysed. LLLT resulted in 23 per cent less root resorption compared to the placebo (P = 0.026). Pulsed laser delivery resulted in 5 per cent less root resorption than continuous; however, this was not statistically significant (P = 0.823). No harm was observed. Conclusion Teeth treated with LLLT had less total root resorption than placebo-laser. Furthermore, there was minimal difference between pulsed or continuous delivery of LLLT. Trial Registration Clinical Trials Registry (ACTRN12616000829415). Protocol The protocol was not published before trial commencement.

Physical properties of root cementum: Part 26. Effects of micro-osteoperforations on orthodontic root resorption: A microcomputed tomography study

Introduction Studies have demonstrated the potential efficacy of micro‐osteoperforations in accelerating tooth movement by amplifying the expression of inflammatory markers. The aim of this investigation was to examine the effects of micro‐osteoperforations on orthodontic root resorption with microcomputed tomography. Methods This prospective controlled clinical trial involved 20 subjects requiring extraction of the maxillary first premolars as part of their orthodontic treatment. A buccal tipping force of 150 g was applied to both premolars. Using the Propel appliance (Propel Orthodontics, San Jose, Calif), micro‐osteoperforations were applied at a depth of 5 mm on the mesial and distal aspects in the midroot region of the experimental side of the first premolar root; the contralateral side served as the control. After 28 days, both premolars were extracted. The teeth were scanned under microcomputed tomography, and the volumes of root resorption craters were calculated and compared. Results Premolars treated with micro‐osteoperforation exhibited significantly greater average total amounts of root resorption than did the control teeth (0.576 vs 0.406 mm3). The total average volumetric root loss of premolars treated with micro‐osteoperforation was 42% greater than that of the control teeth. Conclusions This 28‐day trial showed that micro‐osteoperforations resulted in greater orthodontic root resorption. However, these results should be verified in patients who are undergoing full‐length orthodontic treatment. HighlightsMicro‐osteoperforations were associated with an increase in root resorption after 4 weeks of orthodontic tooth movement.Future studies should be done on patients having a full course of orthodontic treatment.

Exploiting Communication Opportunities in Disrupted Network Environments

The capability of a mobility model to detect certain patterns of user behavior (e.g., favorite walks or walking habits) enables solutions for a number of challenging networking problems, including efficient opportunistic communications and handoff/cellular planning. We argue that the limited viewpoint of a single mobile node and its scarce resources (e.g., energy, memory or processing) are major obstacles for accurate estimations. Targeting at hybrid network environments, we offload prediction capabilities to the fixed nodes that may be available in the area, offering a global view and the capability of resource-demanding calculations.

On the Variances and Convariances of the Duration State Sizes of Semi-Markov Systems

In the present article we study the asymptotic behaviour of the sequence of vectors with components expectations, variances, and covariances of the state sizes of a semi-Markov system. In this respect, we transform the semi-Markov system into a Markov system with a different though equivalent state space and relate the sequence of the transition probabilities of the respective Markov system as functions of the parameters of the semi-Markov system. Also, we study the asymptotic behavior of the sequence of vectors with components variances and covariances of the duration state sizes, of the related Markov system, under perturbation of the transition probability matrices. We use the results in the study of asymptotic behavior under perturbation of the sequence of vectors with components variances and covariances of the semi-Markov system.