Biologic response of rapid tooth movement with periodontal ligament distraction

Cone-Beam Computed Tomography Evaluation of Maxillary Sinus Changes in Orthodontic Patients Treated With Extraction of Four First Premolars

The objective of this study was to assess alterations in maxillary sinus mucosa thickness and the distances between the apexes of specific teeth and the maxillary sinus base in adult patients undergoing orthodontic treatment with the extraction of four first premolars. Twenty-one adults, averaging 24.85 years of age, received orthodontic therapy involving the extraction of all four first premolars. Cone-beam computed tomography scans were conducted before and after treatment to evaluate changes. Notably, post-treatment scans revealed a significant increase (P= 0.044) in the distance between the apex of the second premolar and the maxillary sinus floor, with an average augmentation of 1.0141 millimeters. However, no notable alterations were detected in the distances between the apexes of other teeth and the maxillary sinus or in maxillary sinus mucosa thickness. These findings suggest that orthodontic treatment with the extraction of four first premolars may elevate the distance between the maxillary sinus floor and the second premolar apex, which provides a reference for risk assessment and surgical design of first premolar extraction during orthodontic treatment.

Accelerated Orthodontics: Stepping Into the Future Orthodontics

Orthodontic treatment signifies a transformative journey for individuals seeking not only enhanced oral health but also a boost in aesthetics and self-confidence. Nonetheless, the protracted timeline associated with conventional orthodontic care has been a persistent concern for both patients and practitioners. In this comprehensive review, we embark on an exploration of innovative strategies aimed at expediting orthodontic tooth movement (OTM). By doing so, we aspire to curtail treatment duration and mitigate potential risks, ultimately culminating in an elevated and more fulfilling patient experience. Traditionally, orthodontists heavily leaned on surgical techniques to hasten tooth movement. However, the recent landscape of orthodontics has been profoundly shaped by technological advancements and groundbreaking research findings, ushering in an era characterized by the embrace of minimally invasive approaches. These progressive methodologies encompass procedures like Piezocision, Discision, and Microosteoperforation (Alveocentesis). Beyond the obvious benefits of reduced patient discomfort, these techniques significantly truncate treatment periods, a development that addresses a primary concern of many patients. Moreover, this review delves into non-invasive alternatives, including cyclic vibrations, photobiomodulation, direct light electric current, and static or pulsed magnetic fields, as well as systemic and local administration of biological substances and hormones, all of which hold substantial promise in optimizing OTM. Furthermore, our exploration extends to a diverse spectrum of medications that have demonstrated their efficacy in expediting OTM. These encompass NSAIDs, acetaminophen, corticosteroids, bisphosphonates, herbal medicine biomaterials, and synthetic biomaterials like graphene dioxide. Every technique and medication is subjected to meticulous evaluation, taking into account its indications, contraindications, advantages, disadvantages, clinical implications, and limitations. Through this review, we endeavor to equip orthodontic professionals with a profound understanding of these innovative strategies. By doing so, we enable them to make informed decisions, tailored meticulously to meet the unique needs of each patient. In an ever-evolving field like orthodontics, staying abreast of these advancements becomes paramount, ultimately contributing to heightened treatment efficacy and enhanced patient satisfaction. The adoption of these innovative strategies not only holds the potential for improved clinical outcomes but also champions a patient-centric approach that could fundamentally reshape the landscape of orthodontic care.

Effect of stretch frequency on osteogenesis of periodontium during periodontal ligament distraction

OBJECTIVES

Periodontal ligament distraction (PDLD) can accelerate orthodontic tooth movement (OTM). However, the effect of stretch frequency on osseous formation during PDLD remains unclear. Here, we sought to identify the effect of PDLD frequency on the osteogenic remodelling of the periodontium.

MATERIALS AND METHODS

(i) In vitro, five human periodontal ligament stem cell (PDLSC) cultures were randomized to either static conditions or exposure to a cyclic stretch force involving 12% deformation at frequencies of 0.3, 0.5, 0.7 or 1.0 Hz for 12 h, and the osteogenic differentiation of PDLSCs was assessed using Western blotting. (ii) In vivo, 18 beagle dogs underwent orthodontic distalization of bilateral maxillary first premolars. In the test groups, PDLD was performed at a frequency of two or six times/day, while Ni-Ti coil springs were applied to mimic traditional OTM in the control group. The amount of OTM and histological staining was estimated after force loading for 5, 10 and 15 days.

RESULTS

(i) In vitro, the expression of osteogenic-specific markers (runt-related transcription factor 2 [Runx2], type I collagen [COL-I] and osteocalcin [OCN]) increased with the frequency of tensile force, to a peak at 0.7 Hz. (ii) In vivo, both PDLD groups displayed a greater rate of OTM and a higher bone metabolism than the control group. The expression of COL-I and OCN was significantly reinforced in the six times/day-PDLD group in comparison to the two times/day-PDLD group.

CONCLUSIONS

The cyclic stretch force enhances osteogenesis of the periodontium in a frequency-dependent manner.

Orthodontic Retainers-A Critical Review

The achievement of aesthetic, functional occlusion should not mark the end of the orthodontic intervention. To prevent relapse, retention needs advance planning, and may vary in duration. This review aims to present and comment on the available means of retention. The ever-popular, passive Hawley-like removable appliances are credible in maintaining the desired occlusion. Modifications are the removable appliance Wrap Around, having the labial archwire extending to the premolars; the translucent retainer, Astics, a unique aesthetic Hawley-type device; and the reinforced removable retainer, which features a metallic grid reinforcing the acrylic base. Vacuum-formed retainers are easy to fabricate and are readily prescribed. By contrast, fixed retainers are made of orthodontic wire and composite resin bonded on the lingual or palatal surfaces of the anterior teeth. Patient-related variables need evaluation to select the appropriate retainer, while patients ought to realize the importance of retention and comply with offered guidance. Overall, the orthodontist is responsible for keeping the patient informed on the properties and the duration of retention, even before starting active orthodontic treatment.

Orthodontic Retainers-A Critical Review

The achievement of aesthetic, functional occlusion should not mark the end of the orthodontic intervention. To prevent relapse, retention needs advance planning, and may vary in duration. This review aims to present and comment on the available means of retention. The ever-popular, passive Hawley-like removable appliances are credible in maintaining the desired occlusion. Modifications are the removable appliance Wrap Around, having the labial archwire extending to the premolars; the translucent retainer, Astics, a unique aesthetic Hawley-type device; and the reinforced removable retainer, which features a metallic grid reinforcing the acrylic base. Vacuum-formed retainers are easy to fabricate and are readily prescribed. By contrast, fixed retainers are made of orthodontic wire and composite resin bonded on the lingual or palatal surfaces of the anterior teeth. Patient-related variables need evaluation to select the appropriate retainer, while patients ought to realize the importance of retention and comply with offered guidance. Overall, the orthodontist is responsible for keeping the patient informed on the properties and the duration of retention, even before starting active orthodontic treatment.

TAD's for the Derotation of 90° Rotated Maxillary Bicuspids

It is undeniable that the advent of extra-alveolar mini-implants for anchorage purposes has revolutionized the field of Orthodontics. This case report sheds light on an innovative anchorage plan using TADs, to carry out treatment for a 15-year-old female patient. The patient reported to the clinic with a chief complaint of rotated second premolars, crowding, and a deep bite. On examination, it was seen that the patient had a Class I skeletal pattern, Class II subdivision molar relationship, 90-degree maxillary second premolar rotations, crowding in both the arches, and a deep bite. In this case, the clinicians decided to use TADs for premolar derotation as it not only provides a pure rotational couple without any deleterious effects on the adjacent teeth but also helps shorten the overall treatment time. The total treatment time for this case was 10 months.

Rotational relapse of anterior teeth following orthodontic treatment and circumferential supracrestal fiberotomy

Background/purpose

Several factors cause relapse of orthodontically de-rotated teeth after appliance removal. Circumferential supracrestal fiberotomy (CSF) may release the tension on the supra-alveolar fibers following tooth de-rotation, thereby reducing the relapse risk. However, careful identification of the amount and location of relapse enables proper clinical evaluation. We aimed to determine the amount of orthodontic relapse following CSF for de-rotated anterior teeth.

Materials and methods

Eleven patients with 90 orthodontically de-rotated anterior teeth were enrolled. CSF was performed after orthodontic treatment, during fixed retainer placement. Rotational correction and relapse were measured on three casts (preorthodontic treatment, cast 1; postorthodontic treatment + CSF, cast 2; and 12-month follow-up, cast 3). The Wilcoxon test was used to assess significant differences in the tooth rotation angles between casts 1 and 2 and casts 2 and 3. The relationship between the magnitude of relapse and pretreatment severity of rotation was assessed by the point biserial correlation test. The Mann-Whitney U test helped in identifying significant differences in the amount of relapse between maxillary and mandibular teeth.

Results

The mean amount of rotational correction was 14.05°, while the mean amount and percentage of relapse were 1.1° and 10.8%, respectively [0.81° (8%) and 1.44° (14%) for maxillary and mandibular teeth, respectively]. The relapse amount was proportional to the pretreatment rotation severity, and it was larger for the mandibular canines. There was no significant difference in the amount of relapse between the maxillary and mandibular teeth (P = 0.07).

Conclusion

Post-treatment rotational relapse of anterior teeth subjected to CSF was minimal and statistically insignificant after 1 year of follow-up. This validates the promising results of CSF when combined with appropriate mechanical retention for an adequate period.

Clinical performance of intentionally tilted implants versus axially positioned implants: A systematic review

OBJECTIVES

The aim of this review was to determine the clinical performance of dental implants that are intentionally tilted when compared with implants that are placed following the long axis of the residual alveolar ridge.

MATERIALS AND METHODS

A systematic review of the scientific literature using a predefined research question (PICO) and search strategy was undertaken. This search included five electronic databases. Two independent reviewers examined electronic databases and performed a manual review following search strategy to accomplish the item generation and reduction. Included articles were evaluated to determine the level of evidence. Data were extracted only from level I and level II studies, based on the Oxford Centre for Evidence-based Medicine-Levels of Evidence (March 2009). If included studies were homogeneous in nature, data were to be accumulated. However, if included studies were heterogeneous in nature, only descriptive data would be reviewed and analyzed.

RESULTS

A total of 811 articles were identified through the PICO question and search strategy. Detailed review of the abstracts and articles resulted in further item reduction, and 46 articles were included for full-text review. A total of 42 articles were then selected for inclusion in the systematic review. The identified articles included two level I and 20 level II studies. In addition, 15 level IV, one gray literature, and four previous systematic reviews with meta-analyses were also used in the study. The extracted data from the included studies demonstrated heterogeneity that prevented quantitative assessment, and only one level II study directly compared tilted and axially placed implants. Assessment of the descriptive data demonstrated no differences in implant survival, marginal bone loss, prosthesis survival, or patient-reported outcome measures (PROMs) whether implants are placed axially or with intentional inclination of the coronal aspect of the implant toward the distal aspect of edentulous jaws.

CONCLUSIONS

Based upon the systematic review of the literature, an analysis of the descriptive data suggested no differences in clinical performance between implants that are placed in an axial position relative to the residual alveolar ridge when compared with implants that are intentionally tilted toward the distal aspect of edentulous jaws.

Effect of supplemental vibration on orthodontic treatment with aligners: A randomized trial

INTRODUCTION

Supplemental vibration has been reported to accelerate orthodontic tooth movement and reduce discomfort. Our purpose was to investigate the effects of AcceleDent on Invisalign treatment. This randomized clinical trial was carried out in 2 orthodontic private practices with a 1:1 allocation ratio.

METHODS

Adult patients who were beginning their orthodontic treatment were randomly allocated to either an active (A) or a sham (B) AcceleDent Aura device (OrthoAccel Technologies, Inc. Houston, TX). All patients were placed on a 1-week aligner change regimen, and fit was evaluated every 3 weeks. The outcomes were the ability to complete the initial set of aligners and the incisor irregularity measurements for those who completed their regimen of aligners. In addition, aligner compliance, pain levels, and oral health-related quality of life data were gathered from questionnaires. The subjects, investigators, and assessors were all blinded to the treatment arms.

RESULTS

Twenty-seven subjects were randomized into 2 groups (A and B), 1 subject discontinued treatment, and 13 subjects were analyzed in each group. The Fisher exact test showed no significant difference in completion rates between the 2 groups (group A, 77%; group B, 85%; P = 1). Independent-sample t tests showed no significant difference between the final irregularity index or change in irregularity index between the 2 groups. Compliance was similar in both groups. The Wilcoxon rank sum test showed minimal differences in pain levels. Quality of life responses were similar in both groups. No serious harm was observed.

CONCLUSIONS

We found no evidence that the AcceleDent Aura device impacts the ability to complete a series of aligners with a 1-week change regimen or the final alignment achieved in adult patients. It also had no significant effect on the reduction of orthodontic pain or oral health-related quality of life parameters when used with Invisalign.

Effect of follicular dendritic cell secreted protein on gene expression of human periodontal ligament cells

OBJECTIVE

The objective of this study was to investigate the specific roles of follicular dendritic cell secreted protein (FDC-SP), a protein exists in saliva, in the inhibition of calcium precipitation during periodontal regeneration, as well as affect phenotype expression of human periodontal ligament cells (hPDLCs) during the differentiation process.

DESIGN

To investigate this, we applied microarray technology to identify gene expression changes in hPDLCs transfected with FDC-SP and then clustered them according to their biological functions.

RESULTS

One hundred seventy-one genes were found differentially expressed by at least two-fold between FDC-SP -transfected and empty vector-transfected cells. Besides, genes encoding cell-cycle proteins, blood-related and cell differentiation-related proteins tended to be up-regulated after FDC-SP transfection, whereas cytokine/growth factors, signal transduction and metabolism-related genes tended to be down-regulated in hPDLCs overexpression FDC-SP.

CONCLUSIONS

The present study investigated FDC-SP's roles in hPDLCs' phenotype expression, via comparing the gene expression profiles between FDC-SP -transfected hPDLCs and empty vector-transfected cells upon microarray analysis. hPDLCs overexpression FDC-SP appear to display different gene expression patterns. In all, these observations showed a potential of FDC-SP in the maintenance of PDL homeostasis and its ultimate contribution to periodontal would-healing processes.

Surgically facilitated experimental movement of teeth: systematic review

Several surgical techniques based on corticotomy and dental distraction have been developed to improve the movement of teeth and reduce the duration of orthodontic treatment. In this systematic review we have critically assessed published studies on the experimental movement of teeth to find out whether operations such as corticotomy and dental distraction osteogenesis increase the rate of movement, and to find out which biological mechanisms are engaged during surgically facilitated orthodontics, and which complications may be seen. We searched PubMed and Embase for publications until January 2014 and screened the titles and abstracts. Articles that met the inclusion criteria were retrieved in full and assessed independently by 2 of the authors. A total of 22 studies were included, and corticotomy and distraction techniques were the main surgical methods. Generally, all studies reported that movement of teeth was faster after operation than with conventional orthodontics. The peak velocity was always at an early postoperative stage regardless of the surgical technique used. Immunohistological data showed simultaneous regional increases in catabolic and anabolic activity. Histomorphometric data showed more direct resorption of bone and less hyalinisation after operation, and a reduced bone volume density around the surgical site. When present, complications such as root resorption or periodontal problems were minimal. Current experimental animal studies show that procedures such as corticotomy and dental distraction can accelerate the movement of teeth without severe complications because of the regional increase in catabolic and anabolic remodelling.

Osteogenic differentiation of human periodontal ligament cells after transfection with recombinant lentiviral vector containing follicular dendritic cell secreted protein

BACKGROUND AND OBJECTIVE

Follicular dendritic cell secreted protein (FDC-SP), has been identified in human periodontal ligament (PDL) in a recent study. It is suggested that the expression of FDC-SP might be associated with the osteogenic differentiation and mineralization of human periodontal ligament cells (hPDLCs). However, the intrinsic mechanism regarding this is still unclear. The aim of this study was to establish hPDLCs with safe and efficient overexpression of FDC-SP and to elucidate the influence of FDC-SP transfection on hPDLC osteogenesis in periodontal regeneration.

MATERIAL AND METHODS

We first applied a recombinant lentiviral vector containing FDC-SP to transfect hPDLCs via different multiplicity of infection (MOI) levels (1, 10, 20, 50 and 100). Western blot was performed to confirm the expression of FDC-SP. MTT assay was employed to evaluate the proliferation status of transfected cells. Then, the extent of osteogenic differentiation was investigated by simultaneous monitoring of alkaline phosphatase (ALP) activity assessment, immunofluorescent staining, the expression patterns of osteoblastic markers and mineralization staining.

RESULTS

We found that hPDLCs transfected via MOI 20, 50 and 100 exhibited expression of FDC-SP protein compared with MOI 1 and 10. There was no significant effect of FDC-SP transfection (at different MOI levels of 1, 10 and 20) on the proliferation of hPDLCs, whereas higher MOI levels (50 and 100) inhibited cell proliferation ability. In addition, ALP activity decreased significantly in FDC-SP-transfected hPDLCs at day 7. When stained with alizarin red, cells overexpressing FDC-SP formed less mineralized nodules at 21 d post-induction of differentiation, compared with the control cultures. Osteogenic inhibition was also confirmed by ALP immunostaining. Moreover, mRNA expression levels of osteoblastic markers decreased after FDC-SP transfection, which were in accordance with western blot results.

CONCLUSION

Our data suggest that MOI 20 is optimal to transfect hPDLCs, which achieves safe and efficient overexpression of FDC-SP in transfected cells. Moreover, FDC-SP overexpression inhibits osteogenic differentiation of hPDLCs. The present study contributes to a better understanding of the biological functions governing FDC-SP-induced hPDLC differentiation.

Photobiomodulation accelerates orthodontic alignment in the early phase of treatment

Background

Numerous strategies have been proposed to decrease the treatment time a patient requires in orthodontic treatment. Recently, a number of device-accelerated therapies have emerged in orthodontics. Photobiomodulation is an emerging area of science that has clinical applications in a number of human biological processes. The aim of this study was to determine if photobiomodulation reduces the treatment time in the alignment phase of orthodontic treatment.

Methods

This multicenter clinical trial was performed on 90 subjects (73 test subjects and 17 controls), and Little's Index of Irregularity (LII) was used as a measure of the rate of change of tooth movement. Subjects requiring orthodontic treatment were recruited into the study, and the LII was measured at regular time intervals. Test subjects used a device which produced near-infrared light with a continuous 850-nm wavelength. The surface of the cheek was irradiated with a power density of 60 mW/cm² for 20 or 30 min/day or 60 min/week to achieve total energy densities of 72, 108, or 216 J/cm², respectively. All subjects were fitted with traditional orthodontic brackets and wires. The wire sequences for each site were standardized to an initial round alignment wire (014 NiTi or 016 NiTi) and then advanced through a progression of stiffer arch wires unit alignment occurred (LII < 1 mm).

Results

The mean LII scores at the start of the clinical trial for the test and control groups were 6.35 and 5.04 mm, respectively. Multi-level mixed effect regression analysis was performed on the data, and the mean rate of change in LII was 0.49 and 1.12 mm/week for the control and test groups, respectively.

Conclusions

Photobiomodulation produced clinically significant changes in the rates of tooth movement as compared to the control group during the alignment phase of orthodontic treatment.

Periodontal ligament distraction: esthetics and occlusal stability at the 2-year follow-up

Dental distraction is an orthodontic tooth movement technique that allows closure of extraction spaces, usually of premolars, in periods from 1 to 3 weeks, by bodily retraction of the canine. This article reports on canine distalization by using a distractor device obtained from a conventional hyrax screw. The patient was an adolescent boy, aged 17 years 9 months, who came to the clinic with the chief complaint of tooth crowding. The clinical examination showed a convex profile, retroclined and protruded maxillary incisors, buccally tipped and protruded mandibular incisors, and a Class I malocclusion. The treatment comprised extractions and rapid canine distraction procedures. Pretreatment, posttreatment, and 2-year follow-up records are shown and demonstrate that dental distraction is a viable alternative of treatment. With this treatment strategy, satisfactory results were obtained without additional anchorage devices, achieving an attractive smile and optimal occlusion. The main considerations about the treatment alternatives and their clinical concerns are discussed.

Up-regulated osteogenic transcription factors during early response of human periodontal ligament stem cells to cyclic tensile strain

INTRODUCTION

As one group of periodontal ligament (PDL) cells, human periodontal ligament stem cells (hPDLSCs) have been isolated and identified as mesenchymal adult stem cells (MSCs) since 2004. It has been well accepted that PDL sensitively mediates the transmission of stress stimuli to the alveolar bone for periodontal tissue remolding. Besides, the direction of MSCs differentiation has been verified regulated by mechanical signals. Therefore, we hypothesized that tensile strain might act on hPDLSCs differentiation, and the early response to mechanical stress should be investigated.

MATERIAL AND METHODS

The hPDLSCs were cultured in vitro and isolated via a magnetic activated CD146 cell sorting system. After investigation of surface markers and other experiments for identification, hPDLSCs were subjected to cyclic tensile strain at 3,000 µstrain for 3 h, 6 h, 12 h, and 24 h, without addition of osteogenic supplements. In the control groups, the cells were cultured in similar conditions without mechanical stimulation. Then osteogenic related genes and proteins were analyzed by RT-PCR and western blot.

RESULTS

Cyclic tensile strain at 3,000 µstrain of 6 h, 12 h, and 24 h durations significantly increased mRNA and protein expressions of Satb2, Runx2, and Osx, which were not affected in unloaded hPDLSCs.

CONCLUSIONS

We indicate that hPDLSCs might be sensitive to cyclic tensile strain. The significant increase of Runx2, Osx and Satb2 expressions may suggest an early response toward osteogenic orientation of hPDLSCs.

Pre-clinical evaluation of a new dental panoramic radiographic system based on tomosynthesis method

OBJECTIVES

The purpose of the study was to compare the image generated by a classic panoramic machine equipped with a cadmium telluride sensor capable of digital tomosynthesis and special software with images produced by other popular panoramic X-ray machines using a charge-coupled device and native software for image capture.

METHODS

Panoramic images were made using a phantom of a human skull on Planmeca ProMax, Planmeca EC Proline, Kodak 8000 and PC-1000. With the last machine we used the PanoACT® software to adjust the entire arch and to adjust the image in selected regions of interest (ROIs). Ten viewers evaluated the images and provided the viewer data. ANOVA for repeated measures was used to compare the means by pairwise comparisons of means.

RESULTS

The image of the entire arch adjusted by the PanoACT® software was statistically superior to the images produced by other machines. The images generated and individually adjusted by PanoACT® were statistically superior to all other images.

CONCLUSIONS

The image generated by the cadmium telluride sensor has great potential and can be processed to create superior images to those taken with other machines. Furthermore, the ROI individual images enhanced by the PanoACT® were superior to the entire arch adjusted by the same software.

Retração rápida de caninos

INTRODUÇÃO: a retração rápida de caninos por distração do ligamento periodontal é uma técnica de movimentação dentária que permite o fechamento de espaço da extração de primeiros pré-molares em um intervalo de duas ou três semanas, proporcionando uma redução significativa no tempo do tratamento ortodôntico. OBJETIVO: apresentar modificações propostas na técnica cirúrgica original e no posicionamento dos distratores. CONCLUSÕES: a retração rápida de caninos é uma técnica que proporciona uma redução significativa no tempo de tratamento ortodôntico. A modificação na técnica cirúrgica proporcionou maior velocidade e segurança ao ato cirúrgico. O distrator posicionado por palatina, no mínimo, proporcionou a preservação da tábua óssea vestibular e evitou a vestibularização dos caninos.