vendex and Root-Resorption

Topics: Age Factors; Alveolar Bone Loss; Dental Stress Analysis; Humans; Orthodontics, Corrective; Prognosis; Risk Factors; Root Resorption; Stress, Mechanical; Tooth Apex; Tooth Root; Torque

To evaluate the effects of low-intensity pulsed ultrasound (LIPUS) on orthodontically induced tooth root resorption caused by torque in human subjects.. Ten healthy patients (12-35 years of age) who required extraction of all first premolars as a part of their routine orthodontic treatment were recruited. A 15° twist was applied in the arch wire using 0.019 × 0.025-inch TMA in a 0.022-inch bracket system (Synergy R) that produced a buccal root torque of approximately 5 N/mm at the bracket level. Using a split mouth design, randomization, and blinding, one side of the arch received LIPUS for 20 minutes per day for 4 weeks at an incident intensity of 30 mW/cm(2) of the transducers' surface area. The other side served as a self-control, which received a sham transducer. After 4 weeks, all first premolars were extracted and micro-computed tomographic analysis was performed on these extracted teeth. A linear mixed-model statistical analysis was used.. LIPUS-treated teeth showed significantly less total volume of resorption lacunae compared to control teeth by a mean difference of (0.54 ± 0.09 mm(3)) (P < .001) and percentage of root resorption by a mean difference of (0.33 ± 0.05 mm(3)) (P < .001). In addition, significantly fewer resorption lacunae were found on all root surfaces in the LIPUS group compared to the control except in the instance of the distal surface.. This study was performed on limited number of cases during a 4-week period.. LIPUS minimizes root resorption when applied during torque tooth movement over a 4-week period.

Topics: Adolescent; Adult; Child; Dental Cementum; Double-Blind Method; Female; Humans; Male; Prospective Studies; Root Resorption; Tooth Movement Techniques; Torque; Ultrasonic Waves; Young Adult

Root resorption is an undesirable consequence of orthodontic tooth movement. The severity is unpredictable, and, despite extensive research, the etiology remains unknown. Torque has been acknowledged as a risk factor for root resorption. The aims of the study were to evaluate and quantify the extent of root resorption after the application of 2.5° and 15° of buccal root torque for 4 weeks.. Fifteen patients requiring bilateral extraction of their maxillary first premolars for orthodontic treatment were recruited to the study. By using a standardized experimental protocol, the right and left premolars were randomly subjected to either 2.5° or 15° of buccal root torque. At the end of the 4-week experimental period, the premolars were extracted. A volumetric analysis of root resorption was performed by using microcomputed tomography and measured with specially designed software.. Overall, the amounts of root resorption were comparable after the application of 2.5° or 15° of buccal root torque (P = 0.59). There was a significant difference between the 2 force levels only at the apical region (P = 0.034). More root resorption occurred in areas of compression than in areas of tension. The variables of age and sex were not statistically significant.. Root resorption was evident after 4 weeks of buccal root torque application. More root resorption was seen at the apical region than at the middle and cervical regions. Higher magnitudes of torque might cause more root resorption, particularly in the apical region. As shown in previous studies, the etiology of root resorption is multi-factorial and cannot be explained by mechanical factors alone.

Topics: Adolescent; Age Factors; Bicuspid; Biomechanical Phenomena; Child; Dental Cementum; Female; Humans; Image Processing, Computer-Assisted; Imaging, Three-Dimensional; Male; Maxilla; Orthodontic Brackets; Orthodontic Wires; Risk Factors; Root Resorption; Sex Factors; Stress, Mechanical; Time Factors; Tooth Apex; Tooth Movement Techniques; Tooth Root; Torque; X-Ray Microtomography

To evaluate the difference in root resorption between standard torque self-ligating brackets and high torque self-ligating brackets in bimaxillary protrusion patients after orthodontic treatment.. Pre-treatment and post-treatment Cone beam computed tomography (CBCT) of 32 patients (16 treated with the high torque DamonQ 0.022″ bracket and 16 with the 0.022″ standard torque self-ligating bracket) were selected. The first premolars were extracted from all patients before treatment. After mini-screw implants were inserted into the buccal region between the second premolar and first molar, 150 g of force was applied to retract the upper and lower anterior teeth to close the extraction space on each side. CBCT images of all patients were taken before and after treatment. Three-dimensional reconstruction of the maxillary central incisor, lateral incisor and canine was conducted with Mimics 20.0 software. The volumes of the roots were calculated using Gomagics Studio 12.0 software. The differences between the pre-treatment and post-treatment root volumes were statistically evaluated with a paired-samples t-test.. There was no statistically significant difference in root resorption degree between the two kinds of torque brackets. The patient's degree of root resorption in the high torque self-ligating group was greater than that in the standard torque group.. There was no significant difference in root external apical resorption between the high torque self-ligating brackets and the standard torque self-ligating brackets in bimaxillary protrusion patients.

Topics: Humans; Malocclusion; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Retrospective Studies; Root Resorption; Tooth Movement Techniques; Torque

The amount of apical root resorption when using the torque-segmented archwire (TSA) was investigated as well as the extent and direction of the therapeutically indicated apical movement and the treatment duration.. The degree of apical root resorption in 18 randomly chosen Class II and Class I patients treated with the TSA, as well as in 18 conventionally treated patients were evaluated using pre- and posttreatment panoramic radiographs. The sagittal and vertical apical movements and inclination changes were determined based on pre- and posttreatment lateral cephalograms. Nonparametric tests were applied to test between treatment groups and steps. The Mann-Whitney U test, Kruskal-Wallis, Pearson correlation and Wilcoxon signed-rank test were applied for statistical analysis (p < 0.05).. The incidence of root resorptions was 89-94.4% in low or moderate level. The relative root-crown ratio (rRCR) was not statistically different between the TSA and control groups except tooth 12. The axis of the incisors in the TSA group was significantly improved. The main direction of movement of the apices of the central incisors was retrusion and extrusion. No interdependence between the amount of resorption and the parameters of treatment duration, extent and direction of apical movement were found.. The results of the study showed that the amount of apical root resorption with the TSA is slight to moderate and can be compared to conventional orthodontic treatment. The TSA is hence a suitable method for applying targeted torques to the incisors.. ZIEL: Der Umfang der apikalen Wurzelresorption ebenso wie das Ausmaß und die Richtung der therapeutisch angenommenen apikalen Bewegung sowie die Behandlungsdauer wurden bei Anwendung des Torquesegmentbogens (TSB) untersucht.. Das Ausmaß der apikalen Wurzelresorption wurde an 18 willkürlich ausgewählten Klasse-II- und -I-Patienten, die mit dem TSB behandelt wurden, und an 18 konventionell behandelten Patienten anhand von prä- und posttherapeutisch erstellten Panoramaschichtaufnahmen beurteilt. Die sagittalen und vertikalen apikalen Bewegungen sowie die Änderungen der Inklination wurden anhand der FRS(Fernröntgenseitenbilder)-Aufnahmen bestimmt. Unterschiede zwischen Behandlungsgruppen und -schritten wurden mit nichtparametrischen Tests bestimmt. Mann-Whitney-U-, Kruskal-Wallis‑, Pearson-Korrelation- und Wilcoxon-Rangsummen-Tests wurden zur statischen Analyse verwendet (p < 0.05).. Die Inzidenz der Wurzelresorption betrug 89–94,4 % für geringes bis moderates Ausmaß. Es gab keinen statistisch signifikanten rRCR(„relative root–crown ratio“)-Unterschied zwischen der TSB- und der Kontrollgruppe bis auf Zahn 12. Die Inzisivusachse in der TSB-Gruppe wurde signifikant verbessert. Die Hauptbewegungsrichtung der Apices der zentralen Schneidezähne waren Retrusion und Extrusion. Es fand sich keine Interdependenz zwischen dem Umfang der Resorption und den Parametern Behandlungsdauer, Ausmaß und Richtung der apikalen Bewegung.. Die Studienergebnisse zeigen, dass der Umfang der apikalen Wurzelresorption mit TSB leicht bis moderat ist und mit der konventionellen orthodontischen Behandlung vergleichbar. Der TSB ist daher geeignet, Torque auf die Schneidezähne zu übertragen.

Topics: Humans; Root Resorption; Stainless Steel; Tooth Apex; Tooth Movement Techniques; Torque

Correlating mechanical forces with quantifiable physical changes in the dentoalveolar complex.. Male 6-week C57BL/6 mice (N=3), micro X-ray-computed tomography; post-analysis software to extract physical changes in periodontal ligament (PDL)-space.. Silicone-elastic bands were placed between maxillary molars for 1 week, with the contralateral side as internal control. Average displacements between crowns and roots, and changes in PDL-spaces were evaluated by registering X-ray tomograms of experimental and control hemi-maxillae. Histology illustrated mineral formation and resorption-related events within narrowed and widened volumes of the PDL-space.. 3D maps of changes in PDL-space between molars illustrated coronal and root displacements of 640 μm and 180 μm, respectively, compared to 70 μm in controls. Orthodontic tooth movement (OTM) specimens exhibited an average net change of -20 μm in narrowed and +30 μm in widened PDL-spaces. Bone and cementum were affected by the force on molars, and primary cementum was more affected than secondary cementum.. This novel approach illustrates the importance of 3D-imaging and analysing 3D alveolar socket subjected to OTM otherwise omitted by 2D micrographs. A measured force on the crown elicits a response related to narrowed and widened regions in the 3D complex. OTM that exceeds PDL-space can illicit biological responses that attempt to restore physiologic PDL-space via remodelling of the periodontium. Regenerated weaker bone due to aseptic inflammation caused by orthodontics could leave patients at a higher risk of bone loss or root resorption if they later develop periodontitis, a form of septic inflammation.

Topics: Animals; Biomechanical Phenomena; Dental Cementum; Dental Stress Analysis; Imaging, Three-Dimensional; Male; Maxilla; Mice; Mice, Inbred C57BL; Periodontal Ligament; Radiographic Image Interpretation, Computer-Assisted; Root Resorption; Stress, Mechanical; Tooth Crown; Tooth Movement Techniques; Torque; X-Ray Microtomography

Topics: Adult; Biomechanical Phenomena; Female; Follow-Up Studies; Gingiva; Gingival Recession; Humans; Malocclusion; Orthodontic Retainers; Root Resorption; Stress, Mechanical; Tooth Movement Techniques; Torque; Young Adult

Topics: Dental Stress Analysis; Humans; Iatrogenic Disease; Incisor; Maxilla; Orthodontic Appliances; Periodontal Ligament; Root Resorption; Tooth Injuries; Tooth Movement Techniques; Tooth Root; Torque

Topics: Biomechanical Phenomena; History, 20th Century; Humans; Orthodontic Appliance Design; Orthodontic Brackets; Orthodontic Wires; Root Resorption; Stress, Mechanical; Tooth Movement Techniques; Torque

Miniscrews and miniplates are increasingly being used for absolute anchorage during orthodontic treatment. However, potential problems of damaging adjacent roots and their consequences during mini-implant placement in the alveolar process have not been clearly described.. Animal experiments were used to evaluate the stability of miniscrews placed with intentional root contact. The root repair was evaluated after screw removal. Seventy-two miniscrews were surgically placed in the mandibular alveolar bone of six adult mongrel dogs with metabolic bone labeling at 3-week intervals. Miniscrews of the experimental group were placed so that they contacted the root of the adjacent teeth, were retained for different time durations, and were then removed. The insertion torque, clinical measurements, removal torque, and histological findings were analyzed.. (1) miniscrews contacting the roots showed a significantly higher insertion torque than those without contact; (2) there was a significant difference in the removal torque measurements based on the mobility of miniscrews and the state of root contact; and (3) miniscrews contacting the root were at greater risk of failure.. During placement of miniscrews in the aveolar process, increased failure rates were noticed among those contacting adjacent roots. Failed miniscrews appeared to be surrounded with a greater volume of soft tissue. When more inflammation was present, the adjacent roots seemed to experience more resorption. Nevertheless, the created lesion was repaired with a narrow zone of mineralized tissue deposited on the root surface, which was likely cellular cementum, and was mainly filled with alveolar bone, with the periodontal ligament space being maintained.

Topics: Animals; Bone Screws; Device Removal; Dogs; Miniaturization; Orthodontic Anchorage Procedures; Random Allocation; Root Resorption; Tooth Injuries; Tooth Root; Torque; Wound Healing

To evaluate the risk of root resorption, individual finite element models (FEMs) of extracted human maxillary first premolars were created, and the distribution of the hydrostatic pressure in the periodontal ligament (PDL) of these models was simulated.. A continuous lingual torque of 3 Nmm and 6 Nmm respectively was applied in vivo to the aforementioned teeth. After extraction, FEMs of these double-rooted teeth were created based on high-resolution microcomputed tomographics (micro CT, voxel size: 35 microns). This high volumetric resolution made the recognition of very small resorption lacunae possible. Scanning electron micrographs of the root surfaces were created as well. This enabled the investigation of advantages and disadvantages of the different imaging techniques from the viewpoint of the examination of root resorption. Using the FEMs, the same loading conditions as applied in vivo were simulated.. The results of clinical examination and simulations were compared using the identical roots of the teeth. The regions that showed increased hydrostatic pressure (>0.0047 MPa) correlated well with the locations of root resorption for each tooth. Increased torque resulted in increased high-pressure areas and increased magnitudes of hydrostatic pressure, correlating with the experiments.. If hydrostatic pressure exceeds typical human capillary blood pressure in the PDL, the risk of root resorption increases.

Topics: Bicuspid; Blood Pressure; Dental Stress Analysis; Finite Element Analysis; Humans; Hydrostatic Pressure; Maxilla; Microscopy, Electron, Scanning; Periodontal Ligament; Root Resorption; Tomography, X-Ray Computed; Tooth Movement Techniques; Torque

The purpose of this study was to investigate whether treatment with the Tip-Edge appliance resulted in more apical root resorption (ARR) of the central and lateral incisors during the torquing (third stage) than the non-torquing phases (first two stages) of orthodontic treatment. The three stages of this orthodontic technique make it possible to examine the amount of root shortening during torque separately from other types of tooth movement. The ARR ratio was calculated in 31 Caucasian patients (20 females, 11 males), after the non-torquing stage of treatment and after the torquing phase, by analysing periapical radiographs taken at the beginning of treatment (T1), before the start of the torquing stage (T2), and at the end of treatment (T3). At T1, the mean age was 13 years 6 months (+/- 3 years 3 months). The mean, standard deviation and range of the ARR ratios were calculated and compared (P < 0.001). T-tests were performed to determine levels of significance, at different stages of treatment, between teeth with and without ARR (ARR ratio = 1). Root shortening at T3 was observed for 70 per cent of the central and 76 per cent of the lateral incisors. At T2, ARR was 48 and 53 per cent, respectively. Compared with T2, 38 per cent of the central incisors and 55 per cent of the lateral incisors showed ARR during the application of torque. At T3, the finding for both was 22 per cent. The mean ARR ratio for the central and lateral incisors was the same after the non-torquing stage of treatment but was significantly different from a tooth with no root resorption. After the torquing stage, the ARR ratio for the central incisors was 0.96 and for lateral incisors 0.92. At the end of treatment, the ratio was 0.89 and 0.85, respectively. This study revealed that both the central and the lateral incisors showed comparable amounts of ARR during the torquing and non-torquing stage of Tip-Edge treatment.

Topics: Adolescent; Female; Follow-Up Studies; Humans; Image Processing, Computer-Assisted; Incisor; Male; Maxilla; Orthodontic Wires; Radiography; Root Resorption; Time Factors; Tooth Apex; Tooth Movement Techniques; Torque

To identify clastic cells on the root surfaces of torqued human premolars.. A continuous force of 600 cNmm was applied to upper first premolars in patients 13-16 years of age by using a precise biomechanical model with superelastic wires (NiTi-SE). The 28 teeth in 14 patients were divided into five groups (control [nonmoved], and moved for either 1, 2, 3, or 4 weeks) and processed for tartrate-resistant acid phosphatase (TRAP) histochemistry and transmission electron microscopy.. Mononuclear TRAP-positive cells appeared at 2 weeks, where as large multinucleated TRAP-positive cells were numerous at 3 and 4 weeks. Ultrastructural examination revealed many clastic cells in contact with resorption lacunae. In addition, some cementoblast-like cells appeared secreting new cementum over previously resorbed lacunae.. In general, resorption lacunae and the number of clastic cells, which increased with the duration of the applied force, were found on the cementum surface at the pressure areas. Some signs of cementum repair were also noticed, even with the maintenance of the level of the force.

Topics: Acid Phosphatase; Adolescent; Bicuspid; Cementogenesis; Dental Cementum; Dental Stress Analysis; Elasticity; Histocytochemistry; Humans; Isoenzymes; Microscopy, Electron, Transmission; Orthodontic Wires; Osteoclasts; Periodontal Ligament; Root Resorption; Stress, Mechanical; Tartrate-Resistant Acid Phosphatase; Tooth Movement Techniques; Torque

With the purpose of investigating the occurrence, localization and extension of possible root resorptions after fixed appliance treatment with a continuous torque force, 28 upper first premolars orthodontically indicated for extraction from 14 patients were analyzed by scanning electron microscopy. Tooth movement was carried out with continuous moments of different magnitudes (300 cNmm, and 600 cNmm), using a biomechanical model with superelastic wires (stainless steel-NiTi-SE), which was specially designed and individually calibrated. The teeth were divided into one control group with four premolars (non-moved) from two patients, and two experimental groups (300 cNmm and 600 cNmm respectively) with six patients each. Each group was distributed intra-individually as follows: the right first premolar of six patients was extracted after 1 week of movement, the left first premolars were removed after 2, 3 and 4 weeks. After extraction, teeth were fixed, treated with 2% sodium hypochlorite solution for 6 hours in order to remove the organic tissue components, dehydrated, and metal-coated in a Balzers SCD 050 apparatus.. The analysis in a scanning electron microscope (Jeol 6100, at 10-15 kV) revealed many resorption lacunae in the root surface, mainly on the lingual side in the apical third of the roots. Resorption processes were also observed on the buccal root surface in the cervical third. All experimental teeth showed resorption areas. Teeth which had been moved for a longer time period and with a higher magnitude of applied moments showed a higher degree of root resorption in width as well as in depth. Higher magnitude of moments produced exposure of root dentine, evidencing pronounced root resorption.

Topics: Bicuspid; Humans; Microscopy, Electron, Scanning; Orthodontic Appliances; Root Resorption; Tooth Movement Techniques; Torque

External apical root resorption is a multifactorial problem encountered in all disciplines of dentistry, but it is most commonly seen in cases treated orthodontically. Specific tooth movements that are most likely to exacerbate external apical root resorption are poorly understood. Purpose of the present investigation was twofold: (1) to quantify apical and incisal movements of the maxillary central incisor in the sagittal and vertical planes from cephalograms and (2) to use stepwise multivariate linear regression analyses to see which tooth movements and skeletodental relationships are most predictive of external apical root resorption. The sample consisted of 110 adolescents with similar pretreatment malocclusions (Class I crowded or bimaxillary protrusive) and treatment planned similarly (extraction of four first premolars) by experienced private practitioners. Each of three practitioners used a different orthodontic appliance; the sample was divided proportionately into cases treated with Tweed standard edgewise technique, Begg lightwire technique, and Roth-prescription straightwire technique. Lateral cephalograms were analyzed at the start, middle, and end of treatment. There was no statistical difference in average external apical root resorption between sexes or among techniques. Measures of tooth movement were highly predictive, explaining up to 90% of the variation in root resorption. Apical and incisal vertical movements and increase in incisor proclination were the strong predictors of external apical root resorption for each regression model. Incisor intrusion with increase in lingual root torque together were the strongest predictors of external apical root resorption. In contrast, distal bodily retraction, extrusion, or lingual crown tipping had no discernible effect.

Topics: Adolescent; Cephalometry; Child; Dental Stress Analysis; Female; Humans; Incisor; Linear Models; Male; Malocclusion; Orthodontic Appliances; Predictive Value of Tests; Regression Analysis; Root Resorption; Tooth Extraction; Tooth Movement Techniques; Torque