Search PubMed⌕ Search

SEARCH · Search PubMed

Results for “Tooth Migration”

Search indexed PubMed citations on genomics, clinical trials, systematic reviews and public health. Explore titles, authors and supplied subject terms, then open the PubMed record.

Quote a phrase for an exact phrase match. Source license links do not imply unrestricted reuse.

At least 487 records · Page 27Linked to original sources
PubMed1992

Periodontal force: a potential cause of relapse.

Relapse of aligned mandibular anterior teeth and the progressive collapse of the mandibular arch is a significant problem for orthodontists. However, identification of a specific cause of such relapse has proved elusive. The transseptal fiber system is thought to stabilize teeth against separating forces. It is hypothesized that this fiber system may actually maintain the contacts of approximating teeth in a state of compression, the long-term result of which could be contact slippage and collapse of the arch. The interproximal force (IPF) at the mandibular first molar-second premolar contact was investigated on the basis of previous studies with this representative contact. The IPF was measured in 10 subjects at six different widths of contact separation. By means of graphic plotting techniques, the IPF at zero separation was calculated to estimate the contact force when the molar and premolar were actually touching. The mean IPF at zero separation was found to be 36.7g (SE = 6.6g), and a t test confirmed the hypothesis that a state of compression between contacts exists (p less than 0.0001). After chewing, the mean IPF at zero separation was 57.2g (SE = 9.1g), and a paired t test revealed an increase in contact compression had resulted (p less than 0.01). It was concluded that the periodontium exerts a continuous force on the mandibular dentition and that this force acts to maintain the contacts of approximating teeth in a state of compression. This force is increased after occlusal loading and may help to explain long-term crowding of the mandibular anterior teeth, physiologic drifting of teeth, and maintenance of posterior dental contacts after interproximal wear.

Bite Force↗
PubMed1993

Analysis of stress-strain curves in the rat molar periodontal ligament after application of orthodontic force.

Previous studies have shown that the mechanical strength of the periodontal ligament decreased markedly after application of an orthodontic force to the rat molars. However, an analysis of stress-strain curves obtained from transverse sections of the rat molars has not been made. The present study analyzed the stress-strain curves obtained from the mesial root of the rat mandibular first molar to evaluate the changes of the mechanical properties of the ligament after application of an orthodontic force. An elastic band was inserted between the mandibular first and second molars for 7 days. The maximum shear stress, elastic stiffness, and failure strain energy density were significantly less in the experimental group than in the control group, but the maximum strain was significantly greater. Histologic examinations of the transverse section after mechanical testing showed that the area of the ligament adhering to the mesial surface (compression side) of the socket bone was significantly less in the experimental group. It is suggested that orthodontic forces may cause changes in the constitution of the periodontal collagen, in osteoclastic activity in alveolar bone, and in mineralization patterns of Sharpey's fibers followed by reductions of the mechanical strength of the ligament, particularly on the compression side of alveolar bone.

Alveolar Process↗
PubMed2006

Long-term sequellae of oral appliance therapy in obstructive sleep apnea patients: Part 2. Study-model analysis.

INTRODUCTION: Side effects observed in the occlusion and dental arches of patients using an oral appliance (OA) to treat snoring or sleep apnea for more than 5 years have not yet been investigated. METHODS: Stone casts trimmed in centric occlusion before appliance placement and after an average of 7.4 +/- 2.2 years of OA use in 70 patients were compared visually by 5 orthodontists. RESULTS: Of these patients, 14.3% had no occlusal changes, 41.4% had favorable changes, and 44.3% had unfavorable changes. Significant changes in many variables were found. Patients with greater initial overbites and Class II Division 1 and Class II Division 2 malocclusions were more likely to have favorable or no changes. More favorable changes in overbite occurred in subjects with large baseline overbites. A greater baseline overjet and more distal mandibular canine relationship were correlated to favorable changes. A greater initial overjet was correlated to a more favorable change, a decrease in mandibular crowding, a smaller change in anterior crossbite, and a greater change in overjet. CONCLUSIONS: OA wear after a mean of 7.4 years induces clinically relevant changes in the dental arch and the occlusion.

Analysis of Variance↗
PubMed2004

Administration of MK-801 decreases c-Fos expression in the trigeminal sensory nuclear complex but increases it in the midbrain during experimental movement of rat molars.

Various studies reported c-Fos expression in the neurons in the trigeminal sensory nuclear complex (TSNC) following experimental tooth movement, which implies pain transmission to the central nervous system. Meanwhile, MK-801, a noncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptors, was shown to markedly reduce the expression of c-Fos in the trigeminal subnucleus caudalis (Vc) following noxious stimulation but to enhance c-Fos expression markedly in other brain regions, i.e., the neocortex, dorsal raphe and thalamic nuclei. In the present study, we examined the nature of c-Fos expression in the brainstem including the TSNC and midbrain following administration of MK-801 and/or experimental movement of the rat molars. Twelve hours after the beginning of experimental tooth movement, c-Fos was expressed bilaterally in the superficial laminae of Vc (Vc I/II), dorsomedial areas of the trigeminal subnucleus oralis (Vodm) and rostro-dorsomedial areas of the trigeminal subnucleus oralis (Vor) with the ipsilaterally dominant distribution, but hardly in the periaqueductal gray (PAG), dorsal raphe nucleus (DR) and Edinger-Westphal nucleus (EW). Intraperitoneal administration of MK-801 (0.03, 0.3 and 3.0 mg/kg) prior to the onset of experimental tooth movement reduced c-Fos in the TSNC (Vc I/II, Vodm and Vor) but increased it in the nucleus raphe magnus (NRM), ventrolateral PAG (vl PAG), DR and EW. These results highly emphasize that during experimental tooth movement, a blockade of NMDA receptors induces neuronal suppression in the TSNC but increases neuronal activity in the descending antinociceptive system including the NRM, vl PAG, DR and EW.

Animals↗
PubMed2006

Roles of p38 and ERK MAP kinases in IL-8 expression in TNF-alpha- and dexamethasone-stimulated human periodontal ligament cells.

Orthodontic tooth movement is recognized as a pro-inflammatory stressor of human periodontal ligament (hPDL) cells. However, the cell-signaling pathways linking interleukin-8 (IL-8), intercellular adhesion molecule-1 (ICAM-1), pro-inflammatory cytokines, and dexamethasone in hPDL cells have not been well elucidated. In this study, we investigated the role of mitogen-activated protein (MAP) kinases in dexamethasone- and TNF-alpha-induced IL-8 and ICAM-1 expression in hPDL cells. IL-8 production was measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcriptase-polymerase chain reaction (RT-PCR) analysis. MAP kinase activation and IkappaB degradation were determined by Western blot analysis, and ICAM-1 expression was determined by RT-PCR and FACS analysis. TNF-alpha increased IL-8 mRNA expression and protein secretion in a dose- and time-dependent manner. Dexamethasone suppressed TNF-alpha-induced IL-8 production in a dose-dependent manner. In addition, dexamethasone inhibited TNF-alpha-induced phosphorylation of p38 MAP kinase and extracellular-regulated kinases (ERKs), IkappaB degradation, and NF-kappaB activation. Selective inhibitors for ERKs and p38 attenuated TNF-alpha-induced IL-8 and ICAM-1 expression in the presence and absence of dexamethasone, indicating that MAP kinases play a role in the response of hDPL cells to TNF-alpha. Furthermore, these results suggest that inflammatory cytokine- and dexamethasone-induced IL-8 and ICAM-1, produced via a MAP kinase pathway, may serve as an important mediator of PDL immunoregulation involved in bone remodeling during orthodontic tooth movement.

Anti-Inflammatory Agents↗
PubMed2002

Changes in tooth position in humans in relation to arterial blood pressure.

The three-dimensional physiological tooth movement synchronized with the heartbeat is called periodontal pulsation. This study utilized a computer-assisted amorphous sensor to evaluate the relation between tooth position and arterial blood pressure, and also between the amplitude of periodontal pulsation and arterial blood pressure. The measuring device consisted of a small magnet attached to the tooth and an amorphous sensor that was used to detect displacement of the tooth without actually contacting it. The sample consisted of the upper left central incisors of six healthy Japanese volunteers. The three measuring points for each tooth were on the labial surface. The cold-pressor test was used as an autonomic nerve stimulus that induces an increase in blood pressure and heart rate. Periodontal pulsation, electrocardiogram, blood pressure and heart rate were recorded simultaneously during a 1 min pre-test relaxation, a 2 min cold-pressor test and a 1 min recovery. The results showed significant correlations between tooth position and mean blood pressure in five of the six volunteers and between tooth position and pulse pressure in four. Moreover, it was confirmed that tooth position shifted in the labial direction in conjunction with an increase of the mean blood pressure induced by cold stimulation. Significant correlations were found between the amplitude of periodontal pulsation and pulse pressure in four of the volunteers. These findings suggest that in humans tooth position might be affected by the force of blood pressure transmitted through periodontal vessels and that the amplitude of periodontal pulsation tends to reflect changes of pulse pressure rather than changes in mean blood pressure.

Adult↗
PubMed1978

Nasopalatine duct cyst. An aggressive condition in adolescent Negroes from South Africa?

A retrospective study of the clinical and radiographic features of 51 nasopalatine duct cysts has been undertaken. Of these cysts 33 were in males (64.7%) and 18 in females (35.3%). The age range was 9--67 years (mean 32 years) with most cases being detected between the second and fourth decades. All of the subjects aged less than 20 years were South African Negroes and the lesions found in this group were invariably over 3.5 cm in diameter and rapidly growing. The average size for all of the cysts (after taking in 19% radiographic enlargment factor into account) was 3.5 cm in greatest diameter. The most common signs were: palatal swelling (88.2%), tooth displacement (78.4%) and sub-labial swelling (17.6%). Root resorption was found in only two of the 40 cysts which encroached upon lamina dura. No recurrences occurred following marsupialization or enucleation.

Adolescent↗
PubMed1990

The anterior component of occlusal force. Part 2. Relationship with dental malalignment.

The objective of this study was to determine the relationship between the anterior component of occlusal force and malalignment of the mandibular anterior teeth. The anterior component of occlusal force that resulted from axially loading the second molars was measured in 15 subjects with varying degrees of mandibular anterior dental malalignment. Malalignment of the mandibular anterior teeth was found to be related to the magnitude of the anterior component of occlusal force and to the tightness of interproximal contacts in the mandibular posterior segments.

Adult↗
PubMed1995

Late lower arch crowding: the role of the transverse dimension.

Fifty subjects who were followed longitudinally between 13 and 18 years showed an average increase in lower arch crowding of 2.36 mm. This increase in crowding was examined in relation to tooth width, arch width and jaw width, actual and relative, and to changes in these dimensions with correlation and multiple regression analyses. No relationship was found between width dimensions and late crowding in the lower arch.

Adolescent↗
PubMed1995

Adult versus adolescent Class II correction: a comparison.

The interest of the adult patient in orthodontics has increased as the demographics of the specialty of orthodontics has changed. There are major intreatment and posttreatment differences in Class II malocclusion correction between the adolescent and the adult. This article outlines the differences--and the similarities--between adolescent and adult Class II malocclusion correction. The differences and similarities are illustrated with case reports of a representative adolescent from the adolescent group and a representative adult from the adult group.

Adolescent↗
PubMed1997

A longitudinal study of arch size and form in untreated adults.

Adulthood-the lengthy phase following attainment of biologic maturity-often is perceived as a period of "no change" or one of slow deterioration. Recent skeletodental studies discount this stereotype. Changes in arch size and shape were studied here in a longitudinal series of 60 adults with intact dentitions. Full-mouth study models were taken at about 20 years of age and again at about 55 years. Some variables-particularly those between arches (incisor overbite and overjet, molar relationship) and mandibular intercanine width-remained age-invariant. In contrast, all other measures of arch width and length changed significantly (P < 0.01): Arch widths increased over time, especially in the distal segments, whereas arch lengths decreased. These changes significantly altered arch shape toward shorter-broader arches. The data suggest that changes during adulthood occur most rapidly during the second and third decades of life, but do not stop thereafter. Possible mechanisms driving these changes in tooth position are discussed.

Adult↗
PubMed1999

Three-dimensional dental arch curvature in human adolescents and adults.

The three-dimensional arrangement of dental cusps and incisal edges in human dentitions has been reported to fit the surface of a sphere (the curve of Monson), with a radius of about 4 inches in adults. The objective of the current study was to compare the three-dimensional curvature of the mandibular dental arch in healthy permanent dentitions of young adults and adolescents. The mandibular casts of 50 adults (aged 19 to 22 years) and 20 adolescents (aged 12 to 14 years) with highly selected sound dentitions that were free from temporomandibular joint problems were obtained. The three coordinates of cusp tips excluding the third molars were digitized with a three-dimensional digitizer, and used to derive a spherical model of the curvature of the occlusal surfaces. From the best interpolating sphere, the radii of the left and right curves of Spee (quasi-sagittal plane) and of molar curve of Wilson (frontal plane) were computed. Mandibular arch size (interdental distances) was also calculated. The occlusal curvature of the mandibular arch was not significantly influenced by sex, although a significant effect of age was found (Student t, P <.005). The radii of the overall sphere, right and left curves of Spee, and curve of Wilson in the molar area were about 101 mm in adults, and about 80 mm in adolescents. Arch size was not influenced by either sex or age. The different curvatures of the occlusal plane in adolescents and adults may be explained by a progressive rotation of the major axis of the teeth moving the occlusal plane toward a more buccal position. These dental movements should be performed in a frontal plane on an anteroposterior axis located next to the dental crown.

Adolescent↗
PubMed1999

Postretention mandibular incisor stability after premolar serial extractions.

The purpose of this study was to evaluate the mandibular incisor alignment in serial extraction cases, using the longitudinal dental cast records of the Burlington Growth Center as a control sample. Various parameters were investigated and the statistical differences determined between the treated and untreated groups. The results were also compared with data from serial extraction groups that subsequently had orthodontic treatment. Untreated subjects and subjects treated only with serial extractions showed similar longitudinal changes. However, the extraction group that also received orthodontic treatment appeared to show more lower incisor crowding long-term. No predictors for stability of clinical significance could be determined. Mechanotherapy influences the craniofacial and dentoalveolar dimensions, which appear to cause more long-term lower incisor crowding.

Adolescent↗
PubMed2003

Dental root resorption and repair: histology and histometry during physiological drift of rat molars.

OBJECTIVE: The process of dental root resorption and subsequent cementum regeneration has not been sufficiently elucidated. This study aimed to examine the process of the root resorption and cementum regeneration during physiological tooth drift using a rat model, and to evaluate this experimental model. METHODS: Distal roots in mandibular first molars and the surrounding periodontal tissues were investigated with light and electron microscopy. The light microscopic approach included histochemical and histometric analyses utilizing the tartrate-resistant acid phosphatase (TRAP) reaction. RESULTS: Root resorption was observed in the distal side of the roots and was most active in 5- to 6-week-old rats, and gradually decreased hereafter. An increase in the number of TRAP-positive mononuclear cells, which seemed to be odontoclast precursor cells, preceded the increase in the number of odontoclasts. Root resorption was transient, and was followed by the new formation of acellular extrinsic fiber cementum accompanied with only a slight inflammation, and therefore classified as external surface resorption. Preparation for new cementum started adjacent to the resorption areas when root resorption was most active. CONCLUSIONS: The root resorption during drift in rats is transient and followed by acellular extrinsic fiber cementum regeneration. Cellular kinetics suggested that odontoclast precursor cells are supplied as mononuclear cells from vascular spaces.

Acid Phosphatase↗