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Results for “Root Resorption”

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PubMed1991

Root resorption after local injection of prostaglandin E2 during experimental tooth movement.

The purpose of this study was to investigate the occurrence of orthodontic root resorption in connection with local injection of prostaglandin E2 (PGE2). The material consisted of 25 male Wistar rats. The control group comprised six animals where no force was applied. In five animals 0.1 ml of 0.1 micrograms/microliter PGE2 was injected in the gingival area of the upper right first molar. In one animal no PGE2 was injected. The animals were killed after 3 days. The experimental tooth movement groups consisted of 19 animals. Duration of experiments was 3 days, 7 days, and 10 days. The maxillary first molars on both sides were each moved mesially by means of a coil spring. On the right side 0.1 ml of PGE2 0.1 micrograms/microliters was injected in the gingiva on the buccal side of the upper first molar on days 0, 3, 5, and 7. On the left side no injection of PGE2 was performed. In three animals in the 7-day group the vehicle (Waymouth medium) was injected. There was no significant difference in root resorption between the experimentally moved teeth with and without local injection of PGE2, but a trend towards more root resorption was registered on the teeth where such injections had been performed.

Animals↗

PubMed1985

Nailbiting: frequency and association with root resorption during orthodontic treatment.

The purpose of the present investigation was to determine the incidence and intensity of nailbiting and its possible role in root resorption during orthodontic treatment. A sample of 1365 boys and girls, aged 13-15 years old, were investigated about their nailbiting habits. The possible effect of nailbiting on root resorption during orthodontic treatment was evaluated by radiographic examination of two groups, matched with regard to overjet, age, sex, length and type of orthodontic treatment with fixed orthodontic appliances, one group consisting of 21 severe nailbiters and the other a group of 21 patients without the habit. Replies to questionnaires distributed to 340 boys and girls showed that the incidence of nailbiting was 45 per cent. The habit of severe nailbiting among 1025 of the children investigated was registered in 14.3 per cent. There was no significant difference regarding the habit between boys and girls. The apical root resorption index was significantly higher in the severe nailbiters before (p less than 0.01) and after (p less than 0.001) orthodontic treatment.

Adolescent↗

PubMed2005

Validation of two-dimensional measurements of root resorption craters on human premolars after 28 days of force application.

The aims of this study were to develop a three-dimensional (3D) mathematical model of a typical root resorption crater and to correlate two-dimensional (2D) surface area measurements to 3D volumetric measurements of root resorption craters created under light and heavy orthodontic forces. Data were obtained from a previous study of 36 first premolars from 16 subjects requiring extraction of these teeth as part of their orthodontic treatment. Buccal tipping forces of 25 or 225 g were applied for an experimental period of 28 days. After extraction, the samples were prepared for scanning electron microscopy (SEM) imaging, image processing and analysis. Surface area (2D) and volumetric (3D) measurements of all craters were obtained. A mathematical analysis of the 2D/3D relationship enabled the determination of an appropriate digital model for the shape, type and dimensions of resorption craters, which was also able to distinguish between a 'hemispheric' model versus a 'layered' model of craters. The results demonstrated that 2D and 3D measurements were strongly correlated (r = 0.991**). Within the light and heavy force groups, the measurements were also strongly correlated (r = 0.978** and r = 0.994**, respectively). For a 28 day experimental period, 2D measurements of root resorption craters were found to be as reliable as 3D measurements.

Adolescent↗

PubMed1997

A heritable component for external apical root resorption in patients treated orthodontically.

External apical root resorption (EARR) is a common and occasionally critical problem in orthodontic patients. Mechanical forces compress the periodontium, leading to localized resorption of cementum that exposes dentin to destruction by clastic activity. Factors controlling occurrence and extent of EARR are poorly understood, but there may be a familial (genetic) factor in susceptibility. A sample of full siblings (103 pairs) was studied, all of whom were treated with the same technique by one orthodontist. Crown and root lengths were measured on cephalograms and panoral films before and after treatment. Six roots were scored on each patient, and decrease in root length was the dependent variable. Generalized linear models were used to quantify within and among sibship variances while controlling for sex, age, and severity of malocclusion (FMA, ANB, AOBO, overjet, NAP) as covariates. Results showed significantly greater among-than within-sibship variances, meaning there is a substantive genetic factor in susceptibility to EARR. Heritability estimates were fairly high, averaging 70% for three roots, although low for the mandibular incisor, probably because of little variation. No evidence was found for a sex or age difference in susceptibility. Quantification of a transmissible component suggests it would be useful to search for the biochemical factors controlling the familial differences in susceptibility.

Adolescent↗

PubMed2004

Calcitonin in human odontoclasts regulates root resorption activity via protein kinase A.

Calcitonin is a known inhibitor of osteoclastic bone resorption, but it remains uncertain whether calcitonin also regulates human odontoclastic activity, particularly during the physiological process of root resorption. In this study, we examined the expression of calcitonin receptors in human odontoclasts and the effect of calcitonin on root resorption, using immunocytochemistry and reverse transcription-polymerase chain reaction (RT-PCR). Actin-ring formation was used to assess cytostructural changes during resorption activity. Our results show that calcitonin receptors are expressed in human odontoclasts freshly isolated from deciduous teeth of the periodontal region. Calcitonin inhibited actin-ring formation and resorption activity. This calcitonin-induced inhibition was mimicked by forskolin and dibutyryl-adenosine 3',5'-cyclic monophosphate (db-cAMP), which are protein kinase A (PKA) activators, but not by phorbol 12-myristate 13-acetate, a protein kinase C activator. Pretreatment with adenosine 3',5'-cyclic monophosphothioate Rp diastereomer (Rp-cAMPS), a PKA inhibitor, suppressed the calcitonin-induced inhibition of actin-ring formation. These results indicate that calcitonin receptor activation suppresses odontoclastic root resorption via PKA, a signaling pathway different from that in human osteoclasts.

Acid Phosphatase↗

PubMed1999

Continuous vs. discontinuous force application and root resorption.

The aim of this study was to compare the effects on root resorption of continuous and discontinuous force application. The experimental material consisted of 22 first premolars that were to be extracted as part of orthodontic treatment. Prior to extraction, a 100 g tipping force was applied to the experimental teeth by means of elastics. One side was randomly selected to be the continuous force side, and the contralateral side became the discontinuous force side. Elastics were worn 24 hours per day on the continuous force side and 12 hours per day on the discontinuous side. The experimental procedure lasted 9 weeks. Composite electron micrographs of the buccal surface of each specimen were digitized and areas affected by resorption were determined. The degree of root blunting was assessed by visual scoring. Mean percentage of resorption-affected areas was smaller and apical blunting was less severe on the discontinuous force side. The results of this study show that the application of discontinuous force results in less root resorption than does the application of continuous force.

Adolescent↗

PubMed2000

A radiographic comparison of apical root resorption after orthodontic treatment with a standard edgewise and a straight-wire edgewise technique.

The purpose of this study was to compare the severity of apical root resorption occurring in patients treated with a standard edgewise and a straight-wire edgewise technique, and to assess the influence of known risk factors on root resorption incident to orthodontic treatment. The sample consisted of 80 patients with Angle Class II division 1 malocclusions, treated with extraction of at least two maxillary first premolars. Variables recorded for each patient included gender, age, ANB angle, overjet, overbite, trauma, habits, invagination, agenesis, tooth shedding, treatment duration, use of Class II elastics, body-build, general factors, impacted canines, and root form deviation. Forty patients were treated with a standard edgewise and 40 with a straight-wire edgewise technique, both with 0.018-inch slot brackets. Crown and root lengths of the maxillary incisors were measured on pre- and post-treatment periapical radiographs corrected for image distortion. Percentage of root shortening and root length loss in millimetres were then calculated. There was significantly more apical root resorption (P < 0.05) of both central incisors in the standard than in the straight-wire edgewise group. No significant difference was found for the lateral incisors. Root shortening of the lateral incisors was significantly associated with age, agenesis, duration of contraction period (distalization of incisors), and invagination, while root shortening of the central incisors was related to treatment group and trauma.

Adolescent↗

PubMed2006

Reproducibility of and file format effect on digital subtraction radiography of simulated external root resorptions.

OBJECTIVE: To evaluate, in simulated external root resorptions (ERR), two factors that may affect results of digital subtraction radiography (DSR): (1) intraobserver and interobserver reproducibility and (2) effects of digital file formats (TIFF, BMP and JPEG) on the estimation of mineral loss. METHODS: Eleven incisors were radiographed three times (NR, no resorption; SR, small--#1/4 round bur; and LR, large--#2 round bur) on standardized projections. The resulting images were reproduced and saved as TIFF, JPEG and BMP file formats. The pairs of TIFF images (NR x SR and NR x LR) were subtracted three times at 1 week intervals by three observers. One observer subtracted pairs of images (NR x SR and NR x LR) for all file formats. For each subtraction the resorption area was selected and mean pixel density values were calculated. RESULTS: Analysis of variance (ANOVA) (P = 0.05) showed no statistical differences for intraobserver and interobserver values. Mean pixel density values were: observer A, 121.60 +/- 2.56 (NR x SR) and 111.84 +/- 4.04 (NR x LR); observer B, 121.86 +/- 2.50 (NR x SR) and 110.92 +/- 3.36 (NR x LR); and observer C, 121.70 +/- 2.39 (NR x SR) and 111.10 +/- 2.67 (NR x LR). Also, no statistical differences were found between file formats for LR (TIFF, 110.88 +/- 2.79; JPEG, 111.35 +/- 3.35; BMP, 111.00 +/- 2.70) and for SR between TIFF (121.30 +/- 2.34) and JPEG (120.46 +/- 1.51) or BMP (121.67 +/- 2.18) file formats. Differences were found between the JPEG and BMP groups. CONCLUSIONS: DSR is reproducible in simulated ERR, and JPEG or BMP file formats do not affect results.

Analysis of Variance↗

PubMed1980

Delayed replantation after submucosal storage in order to prevent root resorption after replantation. An experimental study in monkeys.

The purpose of this study was to determine the root resorption pattern of teeth autotransplanted to a submucosal site and to determine whether root resorption after replantation could be prevented by delayed replantation of teeth after submucosal storage in order to regenerate damaged periodontal ligament. Permanent teeth were extracted in green Vervet monkeys. One group of teeth was transplanted to a submucosal site and examined histologically in situ. Another group of teeth was autotransplanted to submucosal sites, recovered and replanted either 2 or 6 weeks later. The animals were sacrificed 8 week after replantation and examined histometrically. The following histologic parameters were registered: surface resorption, inflammatory resorption, replacement resorption (ankylosis), periapical inflammatory changes and downgrowth of pocket epithelium. Teeth autotransplanted to submucosal sites developed surface and inflammatory resorption. In half of the cases where teeth were transplanted with a vital periodontal ligaments new formation of bone took place adjacent to the transplant. Delayed replantation after submucosal burial was not found to inhibit the development of ankylosis, but changed the resorption type from direct apposition of bone upon the root surface to apposition of bone after initial resorption.

Animals↗

PubMed2005

Physical properties of root cementum: Part 5. Volumetric analysis of root resorption craters after application of light and heavy orthodontic forces.

BACKGROUND: In previous studies on root resorption, resorption was quantified by making histologic cuts or by surface area measurements of resorption craters. The aims of this study were to evaluate the effects of orthodontic force magnitude on root resorption craters with volumetric measurements and also to identify the sites that might be predisposed to resorption. METHODS: After an experimental time of 28 days, 36 human premolars previously divided into light-force (25 g) and heavy-force (225 g) groups were extracted and prepared for scanning electron microscope imaging. Pairs of stereo images were taken, and 3-dimensional quantitative volumetric analysis was performed with commercial software. RESULTS AND CONCLUSIONS: The mean volume of the resorption crater in the light-force group was 3.49-fold greater than in the control group; the mean volume of the resorption crater in the heavy-force group was 11.59-fold greater than in the control group ( P < .001). The heavy-force group had 3.31-fold greater total resorption volume than the light-force group ( P < .001). Buccal cervical and lingual apical regions had significantly more resorption craters than the other regions ( P < .001). There was more resorption by volume in the heavy-force group compared with the light-force group and controls. Although more resorption was recorded in the light-force group, the difference in the amount of resorption between the light-force and control groups was not statistically significant. There was significantly more resorption on the buccal cervical and lingual apical regions of the root surfaces than on the other regions, suggesting that high-pressure zones might be more susceptible to resorption after 28 days of force application.

Adolescent↗

PubMed2002

Periodontal 5'-deiodination on forced-induced root resorption--the protective effect of thyroid hormone administration.

The present investigation was designed to study the protective effect given by thyroid hormone (TH) on root resorption: (1) whether intra-peritoneal versus oral TH administration had the same efficiency; and (2) whether this effect involved local or systemic mechanisms. For this purpose, circulating T3 levels, systemic alkaline phosphatase (APase) activity, and 5'deiodinase (5'D) activity were evaluated in the periodontal area of 80 Sprague-Dawley rats, 8 weeks of age, in which orthodontic appliances had been inserted. The results showed that TH-treated animals (intra-peritoneal or oral) had significantly less force-induced root resorptive lesions compared with a control group, without apparent changes in T3 or APase levels, and that periodontal remodelling was accompanied by a significant increase in local T3 generation as a result of T4 deiodination. This 5'D activity was higher in those animals that received exogenous TH. These results suggest that this protective TH mechanism may be achieved at a local level and that administration of low doses of TH may play a protective role on the root surface either during orthodontic treatment or in those patients that present spontaneous root resorptive lesions.

Administration, Oral↗

PubMed1984

Root resorption of upper permanent incisor caused by impacted canine. An analysis of 23 cases.

Unusual root resorption of 12 central and 11 lateral upper permanent incisors in 11 patients is described. The degree of resorption ranged from loss of the apical 1/4 to almost complete loss of root structure. Excepting 1 case, permanent canines were partially or completely impacted and their crowns were in close apposition to the resorbed surfaces of the incisors. The roots of the canines were either in the process of formation or completely formed. The findings suggest that the pressure from the canine which persists in moving downward despite the lack of space to permit normal eruption could cause root resorption of adjacent incisors even in the absence of systemic factors. Of 14 extracted incisors, 10 were replaced orthodontically by the impacted canines, whereas the spaces of the extracted incisors were restored by prosthetic means in the 4 other cases. 6 incisors were preserved without any treatment and 2 with the aid of a sapphire dento-osseous anchor pin. Since the resorbed incisors were mostly free of pain, early detection by radiographic examination is essential to establish a proper diagnosis.

Adolescent↗

PubMed2000

Incisor root resorptions due to ectopic maxillary canines imaged by computerized tomography: a comparative study in extracted teeth.

The purpose of the study was to analyze the ability of computerized tomography (CT) scanning to discriminate maxillary incisor root resorptions caused by ectopically erupting canines. Seventeen maxillary incisors were radiographed in vivo by CT scanning. Contiguous transverse CT scans with a slice thickness of 2 mm were exposed perpendicular to the long axis of the lateral incisors and through the crown of the adjacent, ectopically positioned maxillary canine. Each scan was analyzed and the resorptions on the roots of the laterals were graded according to the maximum depth of the cavity. After the lateral incisors were extracted they were clinically inspected, photographed in different light settings and views, and probed at the contact area between the laterals and the canines. The assessment of the extent of resorption in 4 stages on the CT images compared with the in vitro observations of the extracted roots showed a high degree of agreement for the extent of loss of root substance for all teeth. We conclude that CT scanning performed with good technique accurately reveals tooth root resorption. The presence and influence of the inherent artifacts of tooth root resorption on CT scans are discussed.

Artifacts↗

PubMed2001

[Biology of root resorption process in deciduous teeth. Review of the literature].

Aim of this paper, is to examine, with a review of the literature the different aspects of physiological process of root resorption of deciduous teeth. The process of development of mouth and teeth and their structure is also described. Studies made during the last period, in most part by Japanese authors, improved our knowledge about the process of root resorption of deciduous teeth, even if many aspects are still unknown. The involvement of the pulp and the periodontal ligament and the presence of enzimatic activity and immunologic cells have been confirmed; all these elements seem to have a definite role in the process of root resorption of the deciduous teeth.

Humans↗

PubMed2003

External apical root resorption in Class II malocclusion: a retrospective review of 1- versus 2-phase treatment.

External apical root resorption (EARR) is an imperfectly understood problem of orthodontic treatment. The records of 138 children with Class II malocclusion (overjet > 7 mm) participating in a randomized clinical trial of early orthodontic treatment were reviewed. The patients were treated in either 1 phase with fixed appliances only (n = 49) or 2 phases with headgear (n = 49) or bionator (n = 40) followed by fixed appliances. The 3 groups were similar in age, sex, and malocclusion severity at enrollment. The records examined included anamnestic data, clinical examination records, panoramic radiographs before and after fixed appliance therapy, and posttreatment periapical radiographs. All radiographs were reviewed and scored independently by 2 examiners for maxillary incisor root development, morphology, and EARR. Of the 532 incisors scored, 11% of central and 14% of lateral incisors demonstrated moderate to severe (>2 mm) EARR. The proportion of incisors with moderate to severe EARR was slightly greater in the 1-phase treatment group. There was no difference in the incidence of EARR between teeth that had had trauma and those that had not, and there was only a slight increase in frequency of root resorption in teeth with unusual root morphology. Significant associations exist among EARR, the magnitude of overjet reduction, and the time spent wearing fixed appliances. However, not all incisors in a child respond in the same way, so other variables must play a role in determining the root response to orthodontic forces.

Child↗

PubMed1982

Root resorption following slow maxillary expansion.

In the present investigation the occurrence and nature of root resorption in patients treated with slow maxillary expansion appliances was studied with the aid of radiographs and histological sections from premolars. The radiographs failed to reveal any root resorption, but on the histological sections resorption lacunae were identified. Three types of resorption were distinguished: active, arrested and repaired. The majority of the resorption cavities were located on the bucco-marginal side of the premolars and were of the arrested or repaired type. Examination in polarized light revealed that the reparative cementum was different from normal cementum and that no new attachment had been established between the principal fibres in the periodontal ligament and the reparative cementum.

Adolescent↗

PubMed1994

Inhibitory effect of aspirin on root resorption induced by mechanical injury of the soft periodontal tissues in rats.

The purpose of the present study was to study histologically and histometrically the inhibitory effect of aspirin on root resorption induced by mechanical injury of the periodontal soft tissues in rats. Resorption lacuna in the root surface of the molar in animals given both mechanical injury and aspirin administration contained fewer odontoclasts and was smaller in length and area than that in animals given only mechanical injury. The result of the present investigation indicated that the administration of aspirin might suppress root resorption induced by mechanical injury of the periodontal soft tissues.

Animals↗

PubMed2006

Influence of steroid drugs on orthodontically induced root resorption.

OBJECTIVES: To investigate the effect of acute and chronic corticosteroid treatment on orthodontically induced root resorption. DESIGN: 'Split mouth' design performing orthodontic tooth movement in 64, 6-month-old male rats divided into three groups: acute (n = 22), chronic (n = 23) and control group (n = 19). Acute and chronic group received corticosteroid treatment (8 mg/kg/day) for 3 and 7 weeks, respectively, while no pharmacological treatment was performed in the control group. Performed at the Department of Orthodontics, School of Dentistry, University of Aarhus, Aarhus, Denmark. EXPERIMENTAL VARIABLE: The upper left first molar was moved mesially for 21 days in all three groups with 25 g of force. Undecalcified histological sections were cut at the coronal and apical level. OUTCOME MEASURE: The number of intersections hitting resorption lacunae (ES), defined as a scalloped surface with or without cementoclasts, over the total number of intersections hitting the root surface (RS) were recorded and expressed as percentage. RESULTS: The acute group showed significantly more root resorption at the mesio-coronal level compared with the control and the chronic group. CONCLUSION: This could be ascribed to the lack of balance between blastic activities (inhibited by the drug) and the clastic activities (enhanced or unchanged by drug administration) occurring in the initial phase of drug administration. As a consequence, a careful monitoring of patients undergoing acute corticosteroid treatment is suggested.

Animals↗