Sphingosine-1-phosphate (S1P) is a pleiotropic sphingophospholipid generated from the phosphorylation of sphingosine by sphingosine kinases (SPHKs). S1P has been experimentally demonstrated to ...modulate an array of cellular processes such as cell proliferation, cell survival, cell invasion, vascular maturation, and angiogenesis by binding with any of the five known G-protein-coupled sphingosine 1 phosphate receptors (S1P1-5) on the cell surface in an autocrine as well as a paracrine manner. Recent studies have shown that the S1P receptors (S1PRs) and SPHKs are the key targets for modulating the pathophysiological consequences of various debilitating diseases, such as cancer, sepsis, rheumatoid arthritis, ulcerative colitis, and other related illnesses. In this article, we recapitulate these novel discoveries relative to the S1P/S1PR axis, necessary for the proper maintenance of health, as well as the induction of tumorigenic, angiogenic, and inflammatory stimuli that are vital for the development of various diseases, and the novel therapeutic tools to modulate these responses in oral biology and medicine.
Malocclusion represents the clinically observable endpoint of numerous genetic and environmental influences. Oral Myofunctional Therapy (OMT) aims to treat malocclusions by improving the oral ...environment through re‐education of musculature and respiratory patterns. Although the concept of OMT has existed since the early part of the 20th Century, many of its purported benefits for the treatment of malocclusion remain undemonstrated in the scientific literature. However, a more recent application of OMT for the treatment of Obstructive Sleep Apnoea (OSA) suggests some benefits, although more research is needed to clarify this effect. Prefabricated functional appliances (PFAs) are sometimes advocated as part of myofunctional training programs. In the past decade, controlled clinical investigations have demonstrated that PFAs can improve Class II Division 1 malocclusions in compliant patients. Compared with traditional functional appliances, PFAs might be more cost effective; however, this must be balanced against compliance problems and evidence suggesting that other types of functional appliances might give better treatment results in a comparable time frame.
Mandibular condylar cartilage is categorized as articular cartilage but markedly distinguishes itself in many biological aspects, such as its embryonic origin, ontogenetic development, post-natal ...growth mode, and histological structures. The most marked uniqueness of condylar cartilage lies in its capability of adaptive remodeling in response to external stimuli during or after natural growth. The adaptation of condylar cartilage to mandibular forward positioning constitutes the fundamental rationale for orthodontic functional therapy, which partially contributes to the correction of jaw discrepancies by achieving mandibular growth modification. The adaptive remodeling of condylar cartilage proceeds with the biomolecular pathway initiating from chondrogenesis and finalizing with osteogenesis. During condylar adaptation, chondrogenesis is activated when the external stimuli, e.g., condylar repositioning, generate the differentiation of mesenchymal cells in the articular layer of cartilage into chondrocytes, which proliferate and then progressively mature into hypertrophic cells. The expression of regulatory growth factors, which govern and control phenotypic conversions of chondrocytes during chondrogenesis, increases during adaptive remodeling to enhance the transition from chondrogenesis into osteogenesis, a process in which hypertrophic chondrocytes and matrices degrade and are replaced by bone. The transition is also sustained by increased neovascularization, which brings in osteoblasts that finally result in new bone formation beneath the degraded cartilage.
In Australia and Sweden, orthodontic treatments may be performed by either a general dental practitioner (GDP) or a specialist orthodontist. Evidence suggests that the public may easily confuse a GDP ...who provides orthodontic treatment with a specialist orthodontist. We conducted a survey of people in Australia and Sweden to assess their understanding of the differences between a specialist orthodontist and a GDP who provides orthodontic treatments.
The sample comprised 2006 Australian adults and 1010 Swedish adults who completed an online questionnaire. The survey examined the respondents' understanding of the difference between a GDP and a specialist orthodontist. Demographic data and the respondents’ preference concerning future practitioner type were also collected.
Although most of the responses between the countries were different with statistical significance (P <0.001), many similarities in the responses were observed. More than 90% of the respondents in both countries did not know the difference between a GDP who provides orthodontic treatment and a specialist orthodontist. Almost 75% believed that a specialist orthodontist was the most qualified practitioner to perform orthodontic treatment. Fewer than 10% of the respondents preferred to see a GDP for orthodontic treatment over a specialist. These people tended to be male, have less education, and be younger. Cost was identified as an important factor in choosing an orthodontic practitioner, particularly in the Australian sample.
The clear majority of both Australian and Swedish respondents were unable to identify the difference between a specialist orthodontic and a GDP who provides orthodontic treatments.
•Specialist orthodontists and general dental practitioners provide orthodontic treatment in Australia and Sweden.•Fewer than 10% of respondents could differentiate between the 2 types of providers.•Cost was a significant factor in Australia in choosing an orthodontic practitioner.•Testimonials and location were somewhat less important.
Although there is increasing interest in the use of oral appliances to treat obstructive sleep apnea (OSA), the evidence base for this is weak. Furthermore, the precise mechanisms of action are ...uncertain. We aimed to systematically investigate the efficacy of a novel mandibular advancement splint (MAS) in patients with OSA. The sample consisted of 28 patients with proven OSA. A randomized, controlled three-period (ABB/BAA) crossover study design was used. After an acclimatization period, patients underwent three polysomnographs with either a control oral plate, which did not advance the mandible (A), or MAS (B), 1 wk apart, in either the ABB or BAA sequence. Complete response (CR) was defined as a resolution of symptoms and a reduction in Apnea/Hypopnea Index (AHI) to < 5/h, and partial response (PR) as a > or = 50% reduction in AHI, but remaining > or = 5/h. Twenty-four patients (19 men, 5 women) completed the protocol. Subjective improvements with the MAS were reported by the majority of patients (96%). There were significant improvements in AHI (30 +/- 2/h versus 14 +/- 2/h, p < 0.0001), MinSa(O(2)) (87 +/- 1% versus 91 +/- 1%, p < 0.0001), and arousal index (41 +/- 2/h versus 27 +/- 2/h, p < 0.0001) with MAS, compared with the control. The control plate had no significant effect on AHI and MinSa(O(2)). CR (n = 9) or PR (n = 6) was achieved in 62.5% of patients. The MAS is an effective treatment in some patients with OSA, including those patients with moderate or severe OSA.
Structured
Authors – Chan EKM, Darendeliler MA
Objective – To review and investigate the validity of various 2D quantitative measurement techniques, and to explore the third dimension of root ...resorption.
Design – A review of the literature involving various quantitative evaluation of root resorption.
Results – Quantitative evaluation of resorption using radiographs has proven to be highly inaccurate because of magnification errors and their inability to be readily repeated and reproduced. Studies using histology sections of samples have proven to be laborious and technique sensitive. Inherent parallax errors and loss of material in data transfer have denied the true understanding of this 3D event.
Conclusion – With the evolution in computing technology and digital imaging, the vision of evaluating the extent of root resorption in 3D has materialized. It was demonstrated that 3D volumetric quantitative evaluation of root resorption craters was feasible and its accuracy and repeatability was high.
Background: In previous studies on root resorption, resorption was quantified by making histologic cuts or by surface area measurements of resorption craters. The aims of this study were to evaluate ...the effects of orthodontic force magnitude on root resorption craters with volumetric measurements and also to identify the sites that might be predisposed to resorption.
Methods: After an experimental time of 28 days, 36 human premolars previously divided into light-force (25 g) and heavy-force (225 g) groups were extracted and prepared for scanning electron microscope imaging. Pairs of stereo images were taken, and 3-dimensional quantitative volumetric analysis was performed with commercial software.
Results and conclusions: The mean volume of the resorption crater in the light-force group was 3.49-fold greater than in the control group; the mean volume of the resorption crater in the heavy-force group was 11.59-fold greater than in the control group (
P < .001). The heavy-force group had 3.31-fold greater total resorption volume than the light-force group (
P < .001). Buccal cervical and lingual apical regions had significantly more resorption craters than the other regions (
P < .001). There was more resorption by volume in the heavy-force group compared with the light-force group and controls. Although more resorption was recorded in the light-force group, the difference in the amount of resorption between the light-force and control groups was not statistically significant. There was significantly more resorption on the buccal cervical and lingual apical regions of the root surfaces than on the other regions, suggesting that high-pressure zones might be more susceptible to resorption after 28 days of force application.
Introduction: The aim of this article was to quantify the extent of root resorption in areas of compression or tension under light and heavy buccal tipping orthodontic forces.
Methods: The sample ...consisted of 36 premolars in 16 patients. On 1 side, light (25 g) or heavy (225 g) buccal tipping orthodontic forces were activated for 28 days. The contralateral side in each patient served as the control (0 g). The teeth were extracted, disinfected, imaged under a scanning electron microscope, and analyzed with commercial stereo imaging computer software modified for this study. Buccal and lingual surfaces were divided into 3 equal regions: cervical, middle, and apical. The root surface areas of these regions were documented with straight-on images. Quantification of resorption craters by using volumetric analysis was performed from stereo images taken at ±3°. The degree of resorption was correlated to the amount of surface area under compression or tension.
Results and conclusions: The buccal cervical region had 8.16-fold more root resorption in the heavy-force group compared with the light-force group (
P <.01). The other regions did not seem to have significant differences in the force levels. In the experimental teeth, there was more root resorption in the high-compression regions than in the other regions (
P <.01). There were similar amounts of resorption per unit area on the lingual apical and buccal cervical regions. Regions under compression had more root resorption than regions under tension. There was more resorption in regions under heavy compression than in regions under light compression (
P <.01). There was also more root resorption in regions under heavy tension than in regions under light tension (
P <.01).
Structured
Objective
To investigate the effects of diabetes on orthodontic tooth movement and orthodontically induced root resorption in rats.
Setting and sample population
Twenty‐three 10‐week‐old ...male Sprague‐Dawley rats divided into control (n = 7), diabetes (n = 9), and diabetes + insulin (n = 7) groups.
Materials and methods
Diabetes was induced by administering a single intraperitoneal injection of streptozotocin. Rats with a blood glucose level exceeding 250 mg/dl were assigned to the diabetes group. Insulin was administered daily to the diabetes + insulin group. A nickel–titanium closed‐coil spring of 10 g was applied for 2 weeks to the maxillary left first molar in all rats to induce mesial tooth movement. Tooth movement was measured using microcomputed tomography images. To determine the quantity of root resorption, the mesial surfaces of the mesial and distal roots of the first molar were analyzed using both scanning electron microscopy and scanning laser microscopy.
Results
After 2 weeks, the amount of tooth movement in the diabetic rats was lower than that in the control rats. Root resorption was also significantly lower in the diabetic rats. These responses of the rats caused by diabetes were mostly diminished by insulin administration.
Conclusions
Diabetes significantly reduced orthodontic tooth movement and orthodontically induced root resorption in rats. The regulation of blood glucose level through insulin administration largely reduced these abnormal responses to orthodontic force application.
The purpose of this review is to provide guidelines for the use of oral appliances (OAs) for the treatment of snoring and obstructive sleep apnoea (OSA) in Australia. A review of the scientific ...literature up to June 2012 regarding the clinical use of OAs in the treatment of snoring and OSA was undertaken by a dental and medical sleep specialists team consisting of respiratory sleep physicians, an otolaryngologist, orthodontist, oral and maxillofacial surgeon and an oral medicine specialist. The recommendations are based on the most recent evidence from studies obtained from peer reviewed literature. Oral appliances can be an effective therapeutic option for the treatment of snoring and OSA across a broad range of disease severity. However, the response to therapy is variable. While a significant proportion of subjects have a near complete control of the apnoea and snoring when using an OA, a significant proportion do not respond, and others show a partial response. Measurements of baseline and treatment success should ideally be undertaken. A coordinated team approach between medical practitioner and dentist should be fostered to enhance treatment outcomes. Ongoing patient follow‐up to monitor treatment efficacy, OA comfort and side effects are cardinal to long‐term treatment success and OA compliance.
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