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Results for “Root Resorption”

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PubMed1989

[Fine structure of the root resorption of human deciduous tooth].

During growth and development of the gnathic bone in infants, it is not possible to observe the processes of resorption of the bone and deciduous tooth root, bone formation and calcification of the permanent teeth separately. In the gnathic bone of infants where a normal balance exists between formation of new tissue and resorption, the formative bone tissue is closely related to the cells which give rise to the deciduous and the permanent teeth. We used a scanning electron microscope to observe the fine structure of the root resorption of the deciduous teeth, using root deciduous teeth extracted from humans. Large and small plate-shaped absorbed fossula were found together with projecting dentinal fiber tubuli in the dentinal resorption cavity of the deciduous tooth root. Odontoclasts with a round form supported and covered by fibrous connective tissue were also observed. Furthermore, when the fibrous tissue was removed washed out, an arrangement of calcified collagen fibers (similar to stromal tissue) was found in the cavity. On the absorbed cementum surface a plate-like resorption cavity had formed. The surface was covered by fibrous connective tissue with a regular pattern. The round and oval odontoclasts were surrounded by thick vascular-like connective tissue. High levels of P and Ca were found in the dentinal absorption cavity by X-ray analysis and Al, Mg, Na and Zn were also found. S, P, Ca and Zn were found in the odontoclasts Ca, P, Mg, Na and Zn were found in the cementum resorption cavity.

Humans↗

PubMed2004

Effects of local administration of clodronate on orthodontic tooth movement and root resorption in rats.

Clodronate, a non-N-containing bisphosphonate, strongly inhibits bone resorption and also has anti-inflammatory properties. The purpose of this study was to examine the effect of the local administration of clodronate on orthodontic tooth movement. Both the right and left upper first molars of 26 7-week-old male Wistar rats were moved buccally with a standardized expansion spring. Clodronate solution was injected into the sub-periosteum area adjacent to the left upper molar every third day during the experimental period. The right first molar served as the control. Local injection of clodronate caused a significant (P < 0.001) and dose-dependent reduction in tooth movement in the rats. The number of osteoclasts on the clodronate-injected side was significantly less (P < 0.01) than on the control side. Local clodronate also inhibited root resorption incident to tooth movement. These results suggest that localized use of clodronate could be a useful therapeutic adjunct in orthodontic treatment.

Alveolar Process↗

PubMed1989

Tooth root resorption induced in rats by diphenylhydantoin and parathyroidectomy.

Changes in bone, cartilage and the dentition in animals and man following the administration of anticonvulsant drugs resemble those seen in hypoparathyroidism and pseudohypoparathyroidism. Groups of 21-day-old rats were treated with diphenylhydantoin, parathyroidectomized, or made hypocalcaemic with a calcium-deficient diet. Histological examination revealed extensive resorption of cementum and dentine in the molars of the drug-treated and parathyroidectomized rats, but not in the hypocalcaemic or control groups. Localization of injected tetracycline by fluorescence showed that the resorption affected the distal side of the tooth roots and had occurred after root formation. No changes in cementum formation on the mesial side of the roots had occurred in any of the experimental groups. These results suggest that diphenylhydantoin induces a condition similar to pseudohypoparathyroidism in which the resistance of tooth roots to resorption is reduced.

Animals↗

PubMed1981

Rapid maxillary expansion and external root resorption in man: a scanning electron microscope study.

The effects of rapid maxillary expansion on the external root structure of thirteen appliance-attached and five unattached maxillary first premolars from nine patients have been investigated with the scanning electron microscope (SEM). Topographic features of cementum and dentine resorption, as well as initial and subsequent remineralization changes, are described in detail. All anchor premolars exhibited root resorption, which was mostly confined to the buccal surface. Generally, the longer an anchor tooth remained in fixed retention, the more extensive the buccal root resorption. In contrast, the unattached maxillary first premolars and the opposing mandibular first premolars showed no evidence of resorption. Active resorption was the dominant process in anchor premolars extracted almost immediately after rapid expansion. Subsequently, repair became the predominant process, but continuing resorption was apparent even after 9 months of retention. Repair of root defects occurred by the deposition of cellular cementum which revealed little evidence of principal periodontal fiber reattachment within the advancing mineral front. The resorption pattern identified in the scanning electron microscope was not detected by in vivo radiographic examination. The significance of the findings is discussed.

Activator Appliances↗

PubMed2004

Root resorption: the possible role of extracellular matrix proteins.

During maxillary permanent canine eruption, the deciduous canine root is selectively resorbed while the adjacent permanent lateral incisor root is left intact. An understanding of this selective resorption could provide insights into the cause of moderate to severe iatrogenic root resorption during orthodontic tooth movement. This study investigated the possible role of extracellular matrix (ECM) proteins in the selective resorption process. The spatial expression patterns of 2 ECM proteins, osteopontin (OPN) and bone sialoprotein (BSP), were assessed within the periodontal ligament (PDL) surrounding root surface areas of deciduous and permanent teeth. Intact and resorbed root surface areas from 14 deciduous roots and intact root surface areas from 12 permanent tooth roots were examined. In the deciduous roots, BSP and OPN were locally expressed in the cell layer adjacent to the root surface and most intensely concentrated in areas surrounding and within odontoclasts proximal to the resorptive lacunae. In contrast, BSP and OPN were expressed in a generalized pattern throughout the PDL of permanent roots. These preliminary findings suggest a differential expression of ECM proteins on deciduous versus permanent tooth roots, which could act as a signal for selective odontoclast adhesion to, and subsequent resorption of, deciduous root surfaces.

Extracellular Matrix Proteins↗

PubMed1994

RME-induced root resorption and repair: a computerised 3-D reconstruction.

This study was designed to evaluate the 3-D relation of epithelial rests of Malassez (ERM) to orthodontically induced resorption lacunae in human tooth roots. First premolars were extracted following rapid maxillary expansion, then they were prepared for transmission electron microscopy and sectioned. Serial 1 micron sections were used for the 3-D reconstructions and ultra thin sections were utilized to verify the identification of epithelial cells and blood vessel types. Each serial section was photographed and profiles of the resorption bays, epithelial cells and blood vessels were digitized and computer reconstructions performed with an IBM-based software programme. The reconstructions supported the view that epithelial cell and blood vessel relation to the resorption lacunae appeared to be related to the level of activity of the bay. Possible functional roles for epithelial cells in the resorptive process are discussed.

Adolescent↗

PubMed1986

Root resorption.

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Humans↗

PubMed1986

Root resorption.

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Humans↗

PubMed1974

[Idiopathic root resorption].

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Humans↗

PubMed1982

Root resorption extremes resulting from clinical RME.

An assessment has been made of the area of root surface resorption on extracted RME anchor premolar teeth from eighteen patients held in fixed retention for periods varying between 14 and 52 weeks. The areas of resorption present were extensive but did not increase significantly over the time interval studied. By comparison, the proportion of repair tissue in the defects became greater with the more prolonged retention periods. The topographic findings suggest that strong relapse forces are probably dissipated after 3 months of retention. This investigation showed no correlation between the period of RME, the length of retention, and the total area of resorption affecting the anchor teeth. These findings are discussed in relation to retention following RME.

Adolescent↗

PubMed1984

A radiographic survey of apical root resorption in pulpless permanent teeth.

A radiographic statistical study was performed in order to determine the presence and type of external resorption found in pulpless permanent teeth. Of 1,372 roots evaluated, 49.6% showed resorption. The degree of apical external resorption was significantly related to the presence and size of the periapical lesions in all roots. Much more resorption was found in the roots without root canal filling than in those that were filled.

Adult↗

PubMed1984

Root resorption and tooth movement in orthodontically treated, calcium-deficient, and lactating rats.

Previous studies have shown that chronic dietary deficiency of calcium can result in more rapid orthodontic tooth movement. The purposes of this study were to confirm that finding in a calcium-deficient, lactating rat model and to quantify the degree to which the area of root surface resorption is affected by these conditions. Thirty-five adult female Sprague-Dawley rats were divided into two groups: (1) nonlactating animals on a control diet and (2) lactating animals on a calcium-deficient diet. A 60-gm orthodontic force designed to tip maxillary molars mesially was applied for varying times. At sacrifice, tooth movement was quantified by measuring the space created between maxillary molars; percent bone ash was measured for each humerus, and root surface resorption was estimated by means of a morphometric technique to measure the area of cratering on the mesial roots of first molars. Both groups showed a typical two-phased tooth movement cycle lasting for 10 days, although the magnitude of movement was significantly greater (p less than 0.001) in the test animals. The "humerus" test from animals exhibited a significantly decreased (p less than 0.001) fat-free dry weight, ash, and percent ash weight. The test group also displayed a significantly reduced percent area of root surface resorption (p less than 0.05) by 7 and 10 days following appliance activation. These findings confirm earlier observations that lactation, coupled with calcium deficiency, will produce decreased bone density which is consistent with increased parathyroid hormone secretion.(ABSTRACT TRUNCATED AT 250 WORDS)

Activator Appliances↗

PubMed1974