Effect Of Orthodontic Force Research Articles

The effect of orthodontic forces on autogenous tooth transplantation with complete root formation: a case report

Background and Objectives: Auto transplantation is an alternative treatment for replacing lost teeth when suitable donor teeth are available. This paper presents a case of a successful autogenous tooth transplant.

Effects of orthodontic forces on pulp tissue

Numerous researches on pulp tissue changes caused by orthodontic forces have been performed, among others are: pulp angiogenesis, pulp tissue respiration rate, alkaline phosphatase and aspartate aminotransferase enzyme activities; micro vascular response inside the pulp and the effect of dental movement i.e. extrusion, intrusion, and torque. The result is still controversial, as some researchers claim that orthodontic force has a negative effect, others deny by saying there is no such effect on pulp tissue.

Periodontal concerns associated with the orthodontic treatment of impacted teeth

Impacted teeth are common and are often treated with orthodontic eruption, but periodontal problems associated with the process can evade detection. Profound destruction of the periodontium of an impacted tooth or adjacent teeth can occur. This case report describes the orthodontic eruption of 4 impacted canines in a 19-year-old woman. An open surgical approach was used. Within 6 months of treatment, the maxillary right canine and the lateral incisor experienced severe periodontal destruction, resulting in questionable prognoses for the teeth. Plaque control, periodontal architecture, and subgingival microflora were examined as local etiologic factors of periodontal destruction associated with orthodontic eruption of impacted teeth. Plaque control measures were evaluated, and the consequences of orthodontic tooth movement in the presence of inadequate plaque control were considered. Areas of periodontal architecture made vulnerable by the surgical exposure of the impacted teeth were identified, and the effect of orthodontic force on the periodontium was explored. An increase in putative periopathogens in the subgingival microflora after orthodontic appliance placement was observed. Microbiologic monitoring for pathologic levels of periopathogens and antibiotic therapy were considered. Orthodontic treatment of impacted teeth might require additional professional and personal plaque control measures, 3-dimensional diagnostic imaging, and control of putative periopathogens to preserve the health of the periodontium. (Am J Orthod Dentofacial Orthop 2002;121:639-49)

Gingival response to orthodontic force

Orthodontic tooth movement is brought about by prolonged application of force on the attachment apparatus. This results in cellular and extracellular changes within the periodontium. As shown in numerous studies, tooth movement is achieved after the remodeling of alveolar bone and the response of the periodontal ligament to the mechanical force. Although gingival changes have also been found to be an important factor in the overall response, the effect of orthodontic tooth movement on the gingiva has been investigated to a lesser extent. Unlike bone and periodontal ligament, which regain their original structure after removal of force, the gingival tissue does not regain its pretreatment structure, a fact on which a hypothesis has been made that tooth relapse after removal of retention may be associated with changes in the gingiva. The present review summarizes available data on the effect of orthodontic force on collagen, elastin, and collagenase in the gingiva and its relevance to understanding the mechanism of tooth relapse. (Am J Orthod Dentofacial Orthop 1999;116:152-8)

Effect of orthodontic forces on blood flow in human gingiva.

The relationship of gingival blood flow to the magnitude and duration of applied force was studied in humans using Laser Doppler flowmetry. The sample consisted of five adult volunteers with interdental space between their maxillary central incisors. The labial surface of each central incisor was bonded with a buccal tube and a spring force was applied to close the space. The forces applied were 50 g, 80 g, 120 g, and 250 g. Each force was applied for 30 seconds, 60 seconds, 90 seconds, 5 minutes, and 10 minutes. The blood flow signals were recorded continuously using a pen recorder. Measurements indicated that blood flow was negatively correlated to the amount of force applied. The duration of reactive hyperemia was positively correlated to the duration of force. Laser Doppler flowmetry measures blood flow in superficial periodontal tissues. Yet, the relationship of blood flow changes to the magnitude and duration of orthodontic force suggests that measurements of gingival blood flow may provide a means of estimating physiologic orthodontic forces.

The effects of orthodontic forces on the mechanical properties of the periodontal ligament in the rat maxillary molars

Previous studies have shown that the mechanical strength of the periodontal ligament decreased markedly after the application of an orthodontic force to the rat mandibular first molar. However, the effects of orthodontic forces on the mechanical properties of the periodontal ligament of the other teeth in the same dental arch have not been examined. Furthermore, a detailed analysis of the mechanical parameters has not been made. The purpose of the present study was to analyze mechanical parameters such as maximum shear load, maximum deformation, elastic stiffness, and failure energy in shear, estimated from the load-deformation curves obtained by extracting the rat maxillary molars from their sockets after application of an orthodontic force for 5 days. It was found that the mechanical properties of the periodontal ligament of the rat maxillary molars varied considerably among control teeth in the same dental arch. Decreases in the mechanical properties of the periodontal ligament of the experimental teeth were greatest in the first, less in the second, and least in the third molars. Significant correlations were found between the maximum load and the failure energy and between the maximum deformation and the failure energy in all teeth. It was concluded that orthodontic force affected not only the mechanical properties of the periodontal ligament of the teeth to which the force had been applied but also the mechanical properties of distant teeth.

Effects of orthodontic force on methionine enkephalin and substance P concentrations in human pulpal tissue

Orthodontic treatment typically involves intermittent periods of patient discomfort caused by forces on the teeth and adjacent tissues. This sensation of discomfort presumably is caused by the action of neuropeptides in the peripheral and central nervous systems. The effects of orthodontic force on the concentrations of two endogenous neuropeptides, methionine enkephalin (ME) and substance P (SP), measured as immunoreactive-methionine enkephalin (ir-ME) and immunoreactive-substance P (ir-SP), in human tooth pulp were evaluated in 20 patients from whom premolars were extracted before orthodontic treatment. The teeth from nine controls were not subjected to a force, whereas the 11 experimental patients had force applied to their maxillary premolars either by a transpalatal spring ligature or, in one case, by a headgear. The ligature applied a force within the range of 120 to 245 gm; the headgear applied 600 gm. Reversed-phase high-performance liquid chromatography (RP-HPLC) was used to purify the neuropeptides in the pulp homogenate, and radioimmunoassay (RIA) was used to quantify ir-ME and ir-SP in their appropriate HPLC fractions. (1) Females subjected to orthodontic force had significantly greater ir-ME concentrations than males. (2) The ir-SP concentration decreased significantly from the first to the third tooth extracted, then increased from the third to the fourth tooth. (3) Ir-SP and ir-ME concentrations are positively intercorrelated. The association was highest in the first tooth extracted from controls; surgical extraction decreased the correlation, although it continued to be positive. (4) The concentrations of ir-ME and ir-SP each correlated negatively with the magnitude of the orthodontic force and that correlation was enhanced when the value of the force was log-transformed.

Effects of orthodontic forces on the morphology and diameter of Sharpey fibers of the alveolar bone of the rat.

There is little information available concerning the effects of functional and therapeutic forces on Sharpey fibers and adjacent bone matrix. In the present study, springs were placed between the left first and second maxillary molar teeth of rats and retained for 1, 2, 3, 4, or 5 days. The right side served as a control. Tissues from sham-operated, untreated animals were also studied. Maxillae were removed, fractured, rendered anorganic with sodium hypochlorite, and then examined by scanning electron microscopy (SEM). Some tissues were demineralized and examined by high-voltage electron microscopy (HVEM). Sharpey fibers were studied at the alveolar wall and at the midline of the interdental septum (intra-septal Sharpey fibers). In 5-day experimental tissues, SEM showed intra-septal Sharpey fibers had either a reduced number of, or lacked, unmineralized cores. Unit collagen fibrils in 5-day tissues viewed by HVEM were densely packed into Sharpey fibers which had no afibrillar areas. Sharpey fibers at the alveolar wall demonstrated no observable changes in morphology or in pattern of mineralization. After 5 days of spring placement, the mean diameters of intra-septal fibers were significantly less than those at the alveolar wall (p less than 0.001). The disparity in Sharpey fiber diameters of treated and untreated control animals suggests that untreated controls are essential to the design of studies of rodent tooth movement. This study suggests that orthodontic tooth movement produces changes in the morphology and mineralization patterns of Sharpey fibers which might affect the mechanical strength of the periodontium.

The effect of orthodontic force on concentrations of enkephalins and substance P in human pulpal tissue: William G. ParrisUniversity of Tennessee, Memphis, 1985

The effect of orthodontic force on concentrations of enkephalins and substance P in human pulpal tissue: William G. ParrisUniversity of Tennessee, Memphis, 1985

The enkephalin response in human tooth pulp to orthodontic force

Public perception is that dentistry and pain go hand in hand; thus, pain and pain control are important considerations to the profession. Recent studies have attempted to discover the precise metabolic events involved in neural transmission of nociceptive information. One focus has been the study of peptidergic pathways, which purportedly inhibit the firing of pain-conducting fibers. The research described in this article defined the existence of one enkephalin, methionine enkephalin (ME), in an extract of human tooth pulp tissue and the effect of orthodontic force on that ME concentration. One set of patients who had premolars extracted for orthodontic purposes served as controls. Another set, also diagnosed for premolar extractions, had a coil spring attached between the left and right maxillary premolars to supply an orthodontic force for a period of time prior to extraction. High-performance liquid chromatography, radioimmunoassay, radioreceptor assay, and mass spectrometry were used in a series of experiments to isolate, identify, and quantify ME in the pulp tissues. Principal results were as follows: (1) for the first time ME was detected in human tooth pulp, (2) orthodontic force caused a significant decrease in ME concentrations in the group of experimental teeth compared with controls, and (3) ME levels of the first spring-attached tooth that was removed from each patient had a statistically significant inverse log-linear relationship to the amount of applied force. These data indicate that orthodontic force mobilizes at least one neuropeptidergic pathway in the human tooth pulp.

Effects of orthodontic force on enamel formation in normal and hypocalcemic rats.

Maxillary incisors of young rats fed a diet deficient in calcium and vitamin D for 4 weeks developed hypoplastic enamel surfaces. In the enamel of maxillary incisors of deficiently fed rats as well as in normal rats, an orthodontic force (50 gm) acting on their incisors for 3-7 days induced foldings in the enamel, globular projections from the surface and marked hypoplastic defects. However, the orthodontic force produced clusters of free-lying enamel matrix only in the nutritionally deficient rats. In view of these observations, it might be concluded that disturbances in enamel formation which cause hypoplasias can be caused both by mechanical trauma and hypocalcemia. Furthermore, it seems that hypocalcemia increases the susceptibility to mechanical trauma of ameloblasts in their secretory stage. Whether the changes in enamel formation noted in the hypocalcemic rats is a direct effect of lowered serum calcium or due to the increase in parathyroid hormone is not known at present.

Effects of orthodontic forces and anti-inflammatory drugs on the mechanical strength of the periodontium in the rat mandibular first molar

The mechanical strength of the periodontium was examined by extracting the rat mandibular first molar from its socket in the dissected jaw following application of orthodontic forces. Rubber elastic bands of increasing sizes were inserted between the first and the second molars and following injections of anti-inflammatory drugs, hydrocortisone and indomethacin for 7 days. Marked decreases of the mean ultimate loads to extract the teeth were found following application of the orthodontic forces. Increases of the ultimate loads were found following injections of hydrocortisone and indomethacin. The distances pulled to reach the ultimate loads which seem to represent the extensibility and elasticity of the periodontium correlated closely with the ultimate loads. The orthodontic forces applied were estimated to be about 0.7 kilograms at the end of the experimental period. It was suggested that the mechanical strength of the periodontium is maintained by the organization and constitution of the periodontal collagen fibers, and by the attachment of fibers to the bone, which could be affected by orthodontic forces and by anti-inflammatory drugs.

The effect of orthodontic forces on pulp respiration in the rat incisor

Maxillary central incisors of Sprague-Dawley rats were orthodontically stressed for 72 hours. Radiorespirometry was used to determine the effects of orthodontic tooth movement on the pulp tissue. Results indicated that orthodontic stresses produced a statistically significant increase in the pulp respiration rate.

An experimental study on the effect of orthodontic force on the maxillary first molars by the Kloehn's headgear.

An experimental study on the effect of orthodontic force on the maxillary first molars by the Kloehn's headgear.

The effects of orthodontic force on replanted teeth: A radiographic survey

The effects of orthodontic force on replanted teeth: A radiographic survey