Application Of Intrusive Forces Research Articles

The effect of orthodontic Force Application and Tooth Movement on Dental Pulp

This systematic review aimed to conclusively investigate the effect of continuous intrusive force application on human pulpal blood flow (PBF). It is a well-established fact that applying a severe orthodontic force for an extended period can cause irreversible pulpitis and necrosis in the pulp by accelerating the inflammation process. In contrast, utilizing moderate and intermittent forces allows for ample tooth movement, limits pulp damage, and facilitates pulp healing. Materials and methods: A comprehensive search of published studies was conducted in several electronic databases such as MEDLINE, PubMed, EMBASE, Scopus, Web of Science, CINAHL, and the Cochrane Database of Systematic Reviews, as well as Google Scholar. The search was conducted without limitations to find published studies. The results showed that orthodontic forces can lead to a decrease in pulpal blood flow, which causes a reduction in tooth sensitivity. This reduction is indicated by an increase in response thresholds and more negative responses to tooth sensitivity tests. Conclusion: applying a severe orthodontic force over a prolonged period of time can lead to irreversible pulpitis and necrosis in the pulp due to an increase in the inflammation process. However, using moderate and intermittent forces can facilitate sufficient tooth movement while minimizing damage to the pulp. This highlights the importance of the endodontic-orthodontic interface and the need to consider dental pulp health during orthodontic treatment to avoid dental trauma.

Evaluation of different models of intrusive force application and temporary anchorage device (TAD) placement in total arch intrusion using clear aligners; a finite element analysis

IntroductionPresent study aims to evaluate different models of total arch intrusion using clear aligners in a finite element setup, which might be helpful in gummy smile patients who seek this treatment modality.MethodsFour patterns of intrusive forces were applied on each side of the upper arch aligner model: (1) Distal to the lateral incisors (facial − 80 g) and distal to the first molar (palatal − 150 g). (2) Distal to the lateral incisors (facial − 80 g) and distal to the first molars (facial − 80 g and palatal − 80 g). (3) Distal to the canines (facial − 80 g) and distal to the first molars (facial − 150 g). (4) Distal to the lateral incisors (facial − 80 g) and mesial to the first molars (facial − 150 g). Vertical and horizontal movements of the teeth were measured.ResultsExtrusion movements were solely detected at buccal cusps of the first and second molars in the first model. Palatal movements of posterior teeth were detected in this model. Model II showed a homogeneous intrusion in anterior and posterior teeth and the amount of palatal movements of posterior teeth was reduced compared to model I. In contrast to Model IV, Model III had more intrusion in the posterior compared to anterior teeth. Facial movements of posterior teeth were detected in the third and fourth models. Incisor teeth showed facial movements among all of the models except for the lateral incisor in the third model.ConclusionsEach model of force application, causes different outcomes and side effects which is beneficial in certain clinical situations.

Computation of optimum parameters to achieve the intrusion of mandibular central incisor and mandibular canine for deep bite treatment

Deep bite is a condition in which the maxillary and mandibular arch of teeth overlap with each other. Mandibular central incisor and mandibular canine are extruded significantly in this case. Hence, they need to intrude apically. The segmented arch technique is more effective than any other method for the correction of deep bite. However, there is no significant research to use a segmented arch technique in lingual orthodontics. Hence, the aim of the present research study is to specify accurate tilt (toe) angles in lingual orthodontics (LiO) required for intrusion of the mandibular central incisor and mandibular canine tooth for different positions from respective occlusal plane and to state comparative assessment of required tilt angles for both the teeth. For this purpose, single intrusive force was considered to act from top surface of a lingual bracket of the mandibular tooth. The position of application of intrusive force was considered from two factors, i.e. horizontal distance of bracket top surface from tooth surface and vertical distance of bracket top surface from an occlusal plane. In the present study, four different values of vertical distance of bracket top surface from an occlusal plane were considered. Thus, four different positions of application of intrusive force were considered for both the teeth (mandibular central incisor and mandibular canine). Required (optimum) tilt angles were computed mathematically for each tooth to pass the intrusive force vector through Cres. It is then verified with finite element analysis of CAD models of tooth assemblies. For the mandibular central incisor, the tilt angle was found to be 0° for vertical distance of 3 mm from an occlusal plane (OP). While, for mandibular canine, the tilt angle was found to be 0° for vertical distance of 2 mm from an occlusal plane (OP). Hence, these positions of point of application of intrusive force can be considered as better positions than others clinically.

Intrusion Arches

Orthodontic intrusion is a common treatment approach in managing orthodontic esthetic and functional problems, including gummy smile and deep bite. This review presents contemporary reports related to the intrusion, types of dental intrusion, clinical observations, and the tissue reactions after the application of intrusive force, as well as indications and contraindications for intrusion. This paper concisely describes the fixed and removable appliances used for intrusion accomplishment. Keywords: Biomechanics, Intrusion curve, Orthodontic intrusion.

Torque Control During Intrusion on Upper Central Incisor in Labial and Lingual bracket System - A 3D Finite Element Study.

BackgroundThe aim of present study was to investigate the difference of torque control during intrusive force on upper central incisors with normal, under and high torque in lingual and labial orthodontic systems through 3D finite element analysis.Material and MethodsSix 3D models of an upper right central incisor with different torque were designed in Solid Works 2006. Software ANSYS Version 16.0 was used to evaluate intrusive force on upper central incisor model . An intrusive force of 0.15 N was applied to the bracket slot in different torque models and the displacements along a path of nodes in the upper central incisor was assessed.ResultsOn application of Intrusive force on under torqued upper central incisor in Labial system produce labial crown movement but in Lingual system caused lingual movement in the apical and incisal parts. The same intrusive force in normal-torqued central incisor led to a palatal movement in apical and labial displacement of incisal edge in Lingual system and a palatal displacement in apical area and a labial movement in the incisal edge in Labial systemin. In overtorqued upper central incisor, the labial crown displacement in Labial system is more than Lingual system.ConclusionsIn labial and lingual system on application of the same forces in upper central incisor with different inclinations showed different responses. The magnitudes of torque Loss during intrusive loads in incisors with normal, under and over-torque were higher in Labial system than Lingual orthodontic appliances. Key words:FEM, lingual orthodontics, intrusion, torque control, labial bracket systems

Orthodontic intrusion: A contemporary review

Orthodontic intrusion is a common treatment approach in managing orthodontic esthetic and functional problems, including gummy smile and deep bite. This review presents contemporary reports related to the intrusion, types of dental intrusion, clinical observations, and the tissue reactions after the application of intrusive force, as well as indications and contraindications for intrusion. This paper concisely describes the fixed and removable appliances used for intrusion accomplishment.

Analysis of Stress in the Periodontal Ligament and Alveolar Bone of the Maxillary First Molars during Intrusion with Microscrew Implants: A 3D Finite Element Study

ABSTRACTObjectivesThe objective of this study was to graphically display the pattern and magnitude of stress distribution along the periodontal ligament and the alveolar bone of upper first molars on application of intrusive forces using microscrew implants.Materials and methodsA computer simulation of threedimensional model of maxillary first molars and second molars bilaterally with their periodontal ligament and alveolar bone, with microscrew implants, force element and a transpalatal arch were constructed on the basis of average anatomic morphology. Finite element analysis was done to evaluate the amount of stress and its distribution during orthodontic intrusive force.ResultsOverall maximum stress in this study was seen in the alveolar bone in the implant insertion area of 7.155 N/mm2.Maximum stress in the periodontal ligament was seen in middle third distocervical palatal root surface of the first molar (0.008993 N/mm2). Maximum stress in the enamel was seen in the distal aspect of the cementoenamel junction (0.423 N/mm2). Maximum stress in the dentin was observed in apical one-third of the mesiobuccal root surface of first molar (0.1785 N/mm2).ConclusionIn this study with the use of palatal implant and transpalatal arch, we found that there was no tipping observed during intrusion. This study demonstrates that significant true intrusion of maxillary molars could be obtained in a wellcontrolled manner by using fixed appliances with microscrew implant as bony anchorage.How to cite this articlePavithra AS, Prashanth GS, Mathew S, Shekar SE. Analysis of Stress in the Periodontal Ligament and Alveolar Bone of the Maxillary First Molars during Intrusion with Microscrew Implants: A 3D Finite Element Study. World J Dent 2014;5(1):11-16.

Single Tooth Intrusion simplified with New Removable Orthodontic Appliance: Report of Two Cases

ABSTRACT Intrusion of single anterior tooth done by fixed orthodontic appliance is a tedious procedure for orthodontist as well as for the patient which may be quite expensive and time consuming. The use of a new modified removable orthodontic appliance is illustrated in two case reports in this article which is especially beneficial for such cases. This removable appliance is comprised of a labial bow of 21 gauge stainless steel wire with soldered high labial bow of 19 gauge stainless steel wire which has a soldered hook permitting the use of elastic. Adams clasp and pinhead clasps are used for retention of the appliance. During intrusive force application, one component is for intrusion of tooth and other component is for labial movement. This appliance is fabricated in such a manner that the labial movement is prevented by labial component of wire and is converted into pure intrusive force as much as possible. Force levels used for tooth movement are kept within physiologic limits while using this appliance. A though, this appliance is advantageous over fixed orthodontics due its simpler and quicker chair-side procedure and low cost of treatment associated with patient comfort, patient co-operation is must for the success of this therapy. How to cite this article Mittal AK, Sharma R, Garg P, Sidana A. Single Tooth Intrusion simplified with New Removable Orthodontic Appliance: Report of Two Cases. World J Dent 2014;5(4):232-236.

Intrusion of overerupted maxillary molars with miniscrew implant anchorage: A radiographic evaluation

The aim of this retrospective study was to quantitatively evaluate the treatment effects of intrusion of overerupted maxillary molars using miniscrew implant anchorage and to investigate the apical root resorption after molar intrusion. The subjects included 30 patients whose average ages were 35.5±9.0 years. All patients had received intrusion treatments for overerupted maxillary molars with miniscrew anchorage. There were 38 maxillary first molars and 26 maxillary second molars to be intruded. Two miniscrews were inserted in the buccal and palatal alveolar bone mesial to the overerupted molar. Force of 100-150 g was applied by the elastic chains between screw head and attachment on each side. Lateral cephalograms and panoramic radiographs taken before and after intrusion were used to evaluate dental changes and root resorption of molars. Only 6 of the 128 miniscrews failed. The first and second molars were significantly intruded by averages of 3.4 mm and 3.1 mm respectively (P<0.001). The average intrusion time was more than 6 months. The crown of the molars mesially tilted by averages of 3.1 degrees and 3.3 degrees (P<0.001) for first and second molars. The amounts of root resorption were 0.2-0.4 mm on average. The intrusion treatment of overerupted molars with miniscrew anchorages could be used as an efficient and reliable method to recover lost restoration space for prosthesis. Radiographically speaking, root resorption of molars was not clinically significant after application of intrusive forces of 200 to 300 g.

Open-Bite Treatment of A Case By Means Of Zygomatic Plate Anchorage: A Case Report

Treatment of anterior open bite cases is usually a challenging issue and the treatment results are often hard to maintain. Many treatment modalities were presented throughout the years in the literature where in most, malocclusion is corrected primarily by extrusion of the incisors or preventing passive eruption of posterior teeth. Surgical correction is another main approach in treatment of skeletal openbite cases. However, patients may hesitate to have surgery due to the risks, complexity and costs of this treatment. In this case report a minimally invasive method is shown in which posterior teeth are intruded by using zygomatic anchorage. For this purpose multi purpose implants were placed on the zygomatic buttress area to act as anchorage units. The intrusive force application was started by attaching two 9mm NiTi coil springs bilaterally to the bended “I” shaped processes that access to the oral cavity through the mucosa. Posterior dentoalveolar intrusion was achieved in 6 months and the intrusion was maintained with wire ligation between the implant and the molar tubes throughout the treatment. Lower face height to total face height ratio decreased by 1%. 1mm overbite was achieved. Normal smile line concomitant with the lower lip contour and esthetic gingival exposure was also achieved. If intrusion of the posterior teeth is necessary skeletal anchorage through zygomatic multipurpose implants can be used as a good treatment alternative to orthognathic surgery.

Effective Human Pulpal Blood Flow Changes During Brief Intrusive Force Application and Continuous Orthodontic Force Application using Laser Doppler Flowmetry

Effective Human Pulpal Blood Flow Changes During Brief Intrusive Force Application and Continuous Orthodontic Force Application using Laser Doppler Flowmetry

The relation between the point of force application and flaring of the anterior segment.

The purpose of this study was to determine whether application of an intrusive force by an intrusion arch at the distal wings of the lateral incisor brackets causes a change in the axial inclination of the anterior segment. Maxillary incisor intrusion was performed, and records were taken from 40 adolescent patients at the beginning and end of intrusion. Intrusion of the maxillary anterior segment caused a statistically significant mean increase in axial inclination of the central incisor of 8.74 degrees. The following correlations were investigated and found not statistically significant. The correlation between the (1) distance from the point of force application to the center of resistance at the start of intrusion and the change in axial inclination of the incisor, (2) distance from the point of force application to the center of resistance at the start of intrusion and the change in distance from the incisal edge to the distal side of the first molar, (3) distance from the point of intrusive force application to the center of resistance at the start of intrusion and at the end of intrusion, (4) distance from the point of intrusive force application to the center of resistance at the start of intrusion and the change in this distance between start and end of intrusion, and (5) amount of intrusion and the change in axial inclination.

The effect of continuous intrusive force on human pulpal blood flow.

The purpose of this study was to examine the effect of continuous intrusive force application on human pulpal blood flow (PBF). Recordings were made of 13 vital upper left central incisors in 13 healthy participants (experimental group, n = 8; control group, n = 5) who had clinically healthy tooth crowns and periodontal tissues. PBF was recorded by means of a laser Doppler flow meter (LDF) with an opaque rubber dam applied to the teeth. The basal blood flow in the pulp (BBFP) was compared during three observation periods: (1) before orthodontic archwire engagement; (2) during wire engagement (control group: no application of force; experimental group: continuous intrusive force of 0.5 N); and (3) after the removal of the wire. In the experimental group, brief intrusive forces (magnitude 0.5, 1.0, and 2.0 N) were applied to the incisal edge of the examined teeth to determine their effect on acute changes in PBF. The results obtained were as follows: (1) the BBFP in the experimental group was significantly reduced during the period of continuous intrusive force application (P < 0.05), which was followed by recovery after the removal of the wire. (2) Brief intrusive force produced a significant reduction of PBF (P < 0.05), but the reduction rate (percentage) did not differ significantly during the observation periods. The results indicate that the measurement technique shown in this study could detect PBF change produced by continuous orthodontic force application.

Histological and histochemical quantification of root resorption incident to the application of intrusive force to rat molars.

This study was conducted to investigate the nature of root resorption resulting from intrusive forces applied to the rat lower molars, by means of histological and histochemical techniques with tartrate resistant acid phosphatase (TRAP). Thirty-eight 13-week-old Wistar strain male rats were used. Intrusive force was created by a fixed appliance which was adjusted to exert an initial force of 50 g for the duration of 1, 2, and 3 weeks. The degree of root resorption and distribution of TRAP positive cells were evaluated. On the root surface, the TRAP positive scores were low in the apical regions. Significant differences in the scores were found in the inter-radicular region of the roots between the experimental and control groups for the 2- and 3-week groups. More active resorption of bone occurred during the experimental period, as denoted by greater TRAP positive scores on the bone than on the root surface. Root resorption scores in the apical root region were larger in the 2- and 3-week groups than in the 1-week group. Significant differences in the root resorption scores were also found between the 1- and 3-week groups in the inter-radicular region, indicating that intrusive force application of a longer duration may lead to a higher frequency of root resorption. It is shown that, irrespective of the level of TRAP positive cells and root resorption scores, the degree of root resorption activity is higher in the apical root region than in the inter-radicular area. These results indicate that cellular cementum may be resorbed more easily because of its richer organic components and low mineralized structure.

Tissue changes in the rat molar periodontium following application of intrusive forces

The effect of intrusive forces on periodontal structures has been studied in maxillary molars of 55 young male rats. The tissues in the interradicular and apical regions had the typical characteristics of pressure zones: periodontal ligament compression, cellfree and semi-cellfree zones and initial undermining bone resorption in the earlier phases of the force application, a widening of the periodontal space, a decrease in the incidence of cellfree and semi-cellfree zones, bone and root resorption in the later phases. In the marginal and middle third region of the periodontium the characteristics of pressure zones and tension zones were found in the same areas: cellfree and semi-cellfree zones, bone and root resorption, stretched fibres and deposition of osteoid tissue. Bone resorption was also observed on the alveolar crest, bone deposition on the external maxillary surface adjacent to the root apices. The reaction to forces of different magnitude, varying between 0.29 and 0.98 N was essentially the same. However, the incidence of cellfree zones and root resorption lacunae seemed to increase as the force increased.