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At least 19 recordsLinked to original sources
PubMed1992

[Root resorption].

Root resorption can be divided into two main categories: internal root resorption and external root resorption. Internal root resorption is a pathology that can lead to tooth destruction in the short term and must consequently be stopped as soon as possible by applying adequate canal treatment. Until now, despite many research studies, very little is known about its causes and the way this kind of resorption appears. There are many different forms of external root resorption and it has a very diverse etiology. An external root resorption can thus appear in case of orthodontic treatment or due to the pressure brought by cysts, tumours or impacted teeth. A trauma or an infection may also lead to the development of an external root resorption. Because they are so diverse, each of these forms of external root resorption requires a specific treatment. It should also be noted that internal root resorptions, and some forms of external resorption too, often respond favourably to a calcium hydroxide treatment.

Calcium Hydroxide↗
PubMed1992

Factors regulating and modifying dental root resorption.

A comparison is made between the resorption of bone and the resorption of the mineralized tissues of teeth. The structure and function of osteoclasts are described well as the factors that regulate their activity. The cells resorbing the dental mineralized tissues are of the same cell type as osteoclasts. The dental tissues are covered by cementoblasts or odontoblasts which differ from the osteoblasts in that they do not respond to hormones and cytokines that stimulate bone resorption. Root resorption therefore seem to require damage of the cementoblastic layer in combination with necrosis or inflammation or replacement of the cementoblastic layer by osteoblasts. The root resorption that occurs at the shedding of the primary teeth is induced in a different way possibly by substance(s) from the reduced enamel epithelium. There seems to be no systematic study on the frequency and extension of root resorption in association with inflammatory or neoplastic conditions. It is suggested that dentigerous cysts and some epithelial tumors induce root resorption in the same way as the erupting tooth. The mechanisms by which some other tumors or tumor-like conditions cause root resorption are essentially unknown.

Animals↗
PubMed1991

Histological characterization of bleaching-induced external root resorption in dogs.

External root resorption occasionally develops after intracoronal bleaching with hydrogen peroxide. In this study, an experimental model was established to study thermocatalytic bleaching-induced root resorption in dogs. Histological examination after 6 months revealed that 18% of the teeth had root resorption lesions. The lesions could be divided into three types. In type I, root excavations were associated with a dense inflammatory cell infiltrate. Type II lesions were characterized by granulation tissue formation. In type III, the lesions were filled with reparative cementum. The three types probably represent different phases of one process. Calcium hydroxide had no effect on the occurrence or type of resorption. The instability of hydrogen peroxide and the presence of inflammatory resorption lesions 6 months postoperatively suggest hydrogen peroxide-induced toxic radicals or denaturants as potential irritants.

Animals↗
PubMed1991

Periodontal repair in dogs: effect of root surface treatment with stannous fluoride or citric acid on root resorption.

This study evaluated healing, with emphasis on root resorption, following root surface treatment with 1% aqueous stannous fluoride (SnF2), saturated citric acid (CA), or saline control (C) in conjunction with periodontal flap surgery. Supraalveolar periodontal defects were surgically created and immediately treated in the mandibular premolars in 6 beagle dogs. The defect height approximated 5 to 6 mm from the reduced alveolar bone to the cemento-enamel junction. Root treatments were rotated between experimental teeth within jaw quadrants and duplicated in left and right quadrants in the dogs. Flaps were raised to cover most of the crowns of the teeth and sutured. The dogs were sacrificed 12 weeks after surgery and tissue blocks with teeth and adjacent structures were processed for histometric analysis. SnF2-treated teeth healed with significantly longer junctional epithelium, less connective tissue repair to the root surface, and less bone regeneration than CA and C-treated teeth. New cementum formation was limited in all treatment groups. Root resorption was observed in almost all teeth exhibiting connective tissue repair, however to a lesser amount and not as frequent in SnF2 treated teeth due to limited connective tissue repair. No differences were found in amount and frequency of root resorption in CA and C-treated teeth. An inhibitory effect on root resorption of SnF2 could not be disclosed in this experiment, however, it may be concluded that CA treatment of the root surface in conjunction with reconstructive periodontal flap surgery does not seem to enhance root resorption.

Alveolar Process↗
PubMed1992

Physiological root resorption of primary molars.

Physiological root resorption of primary molars was assessed using bitewings and orthopantomograms. Thirty-six per cent of teeth examined demonstrated reduced root resorption of one or more roots. Excepting the lower first primary molar, the present study recorded a relatively high incidence of uneven root resorption during the exfoliative process, particularly evident for the upper second primary molar. Discrepancy in size between the premolar and its predecessor, as well as the position of the developing permanent tooth in relation to primary root structure influences the pattern of root resorption. Therefore, constant monitoring of teeth demonstrating uneven resorption is required to avoid the complications associated with over-retained teeth.

Child↗
PubMed1990

[Root resorption of vital and endodontically treated teeth in orthodontic movement].

Orthodontic tooth movement frequently induces the resorption of the tooth root, although valuable information concerning the relationship between the root resorption and force magnitude, duration and types of tooth movement and the condition of periodontium obtained. However, it is incompletely known that the situation of candidated tooth itself of orthodontic movement in which pulpectomized non-vital condition influence the process of root resorption and subsequent repairing. Thus, the study was conducted to clarify the effect by the pulpectomy accompanied with tooth movement on the process of root resorption and regeneration of periodontium. A hundred and fifty Wistar rats, weight 180-200 g, 6 weeks old, were used as experimental animals. Prior to experimental tooth movement, first molars of 50 rats were received pulpectomy on both sides followed by filling of root canal (first group) and those of another 50 rats on single side (second group). Maxillary first molars of the other 50 rats were saved as a vital dental pulp control (third group). The first and the third groups of animals were then subjected to experimental tooth movement with the interproximal insertion of elastic rubber as described by Waldo (1953) for 3 days, 1, 2, 3 and 4 weeks. After tooth movement was terminated, animals were sacrificed by ether inhalation or by perfusion of glutaraldehyde fixation solution. The upper jaw from each rat was dissected and prepared specimens for non-decalcified section and light microscopic section. Root resorption and regeneration of cementum were evaluated quantitatively using the modular system for semiautomatic quantitative evaluation of images on the light microscopic section. Occurrence of external root resorption with multinucleated odontoclast associated with experimental tooth movement in pulpectomized tooth were lesser and later than those of vital teeth. These findings suggest that the dental pulp plays an important role in the processes of root resorption and remodeling of cementum associated with orthodontic tooth movement.

Animals↗
PubMed1976

Root resorption by ameloblastomas and cysts of the jaws.

Radiographs of 122 cases of a series of nonmalignant simple jaw cysts and ameloblastomas were examined and the frequency of resorption of adjacent tooth roots compared. The ameloblastomas proved to have a root resorptive potential far greater than the cystic lesions considered. Certain statistically significant differences were observed in the root resorption related to the cystic lesions. The dentigerous cyst showed a tendency to resorb roots (55%), whereas in this study no resorption was observed in primordial cysts. These differences may aid the clinician in the preoperative differential diagnosis. It is suggested that the capacity of the dentigerous cyst for root resorption may be the result of its origin from the dental follicle, which is associated with resorption of the roots of primary teeth during normal tooth succession.

Ameloblastoma↗
PubMed1990

Possible role of cementoblasts in the resorbant organ of human deciduous teeth during root resorption.

Human deciduous teeth undergoing physiologic root resorption were extracted and fixed with a mixture of formaldehyde and glutaraldehyde and processed for scanning (SEM) and transmission (TEM) electron microscopy, and for acid (ACPase) and alkaline phosphatase (ALPase) cytochemistry. The resorbant organ, rich in odontoclasts, cementoblasts, fibroblasts, and macrophages, formed prominent resorption lacunae in root dentin. SEM observations of resorption lacunae treated with trypsin solution showed islands of newly-formed cementum matrix in part of the resorbing dentin surfaces. Such cementum consisted of bundles of densely-arranged collagen fibrils and, in part, contained forming cementocytic lacunae and canaliculi. Active cementoblasts adjacent to odontoclasts on resorbing dentin surfaces showed cuboidal outlines and were characterized by the presence of numerous cisterns of rough endoplasmic reticulum, well-developed Golgi complexes, secretion granules, and many mitochondria. They sometimes formed a thin layer of cementoid and/or cementum matrix upon the resorbing dentin surface. These cementoblasts had ACPase-positive lysosomes in the cell bodies and exhibited intense ALPase activity along the plasma membranes of whole cell surfaces. These results suggest that, during root resorption, 1) active cementoblasts are present adjacent to active odontoclasts and 2) these cementoblasts are involved in remodeling the resorbing dentin surfaces.

Acid Phosphatase↗
PubMed1991

Radiographic observations on root resorption in the primary dentition.

In order to construct standardized charts for root resorption in the primary dentition of Japanese children, we investigated the stages of resorption (1/4, 1/2 and 3/4 of the root) based on the criterion of Fanning, et al. using 11,167 panoramic radiographs (5,759 of boys and 5,408 of girls). The following information was obtained. 1) The root resorption for a tooth on one side was the same as for its counterpart on the other side regardless of differences in sex or arch. 2) The average age for each root resorption stage was lower in girls than in boys regardless of differences in sex or arch. 3) The average age for each root resorption stage was lower in the mandible than in the maxilla for every tooth. 4) In the maxilla, the period between 1/4 to 3/4 resorption of the root was greater in the primary molars than in the primary anterior teeth. However, the opposite was true in the mandible. 5) Although no difference was observed between the maxilla and the mandible in the resorption period for the primary incisors and canines, the resorption time for the primary molars was greater in the maxilla than in the mandible. 6) When the relationship was observed between the resorption stages for each tooth and the calcification stages for the corresponding successional permanent tooth. a) With the exception of the maxillary and mandibular canines, the average age for 1/4 resorption of the primary root corresponded to the period between completion of the permanent crown and initial root formation of the successional permanent tooth. b) With the exception of the maxillary and mandibular canines, and the mandibular second premolars, the average age for 3/4 resorption of the primary root corresponded to the period between 1/4 and 1/2 formation of the root of the successional permanent tooth. From these results, standardized charts were constructed for the resorption of the roots of primary teeth in Japanese children. These standardized charts are useful in daily clinical practice in such areas as endodontic treatment of primary teeth and orthodontics.

Adolescent↗
PubMed1992

A case of progressive external root resorption treated with surgical exposure and composite restoration.

Progressive external, root resorption was observed apical to the alveolar crest on the buccal surface of a tooth. The area of root resorption was surgically exposed. To gain access to the root resorption cavity osteoectomy was performed. The soft tissue in the resorption cavity was removed and a composite filling (Retroplast) was placed in the cavity using a dentine bonding system (Gluma). The pulp was removed and the root canal was obturated with gutta-percha points and root canal sealer (AH26). Eight months after treatment no further root resorption was observed. Increased pocket depth and slight bleeding on probing in the area of resorption were evident.

Bicuspid↗
PubMedDate not supplied

Microscopical aspects of root resorption of human deciduous teeth.

In order to obtain detailed information on the tissue changes which occur during physiological root resorption, 52 human deciduous teeth at various stages of resorption were studied under light microscopy. The early stage of root resorption was defined as resorption of not more than one third of the root length; the late stage was defined as resorption of more than one third. A close topographical interrelationship was found among che sites of pressure of the permanent tooth, the extent of root resorption and the types of tissue changes. Linear resorption (which reflects suspension or marked slowing down of resorption) and redeposition of hard tissue were more pronounced at the early stage of resorption, while lacunar resorption was more pronounced at the late stage. There were pronounced haemorrhagic and inflammatory infiltrates within the pulp at the late stage of resorption and the subodontoblastic cells disappeared as the infiltrates took over the tooth. False denticles were found frequently, especially at the early stage of resorption. Unexpectedly, acellular cementum was found to be deposited against secondary dentine at the cuspidal tip of the pulp chamber of seven teeth, independently of any sign of resorption nearby. These data indicate that: 1) the pressure exerted by a permanent tooth is the most important factor in the differentiation of odontoclasts. 2) the extent of lacunar (i.e., active) resorption correlates directly with the resorption rate, which is higher at the late stage of root resorption. 3) inflammation is a consequence, rather than a cause, of resorption; it may lead to the loss of subodontoblastic cells and a consequent decrease in the ability of the pulp cells to replace damaged odontoblasts. 4) the pulp of the deciduous tooth might be cementogenic in some way, given that about 13% of the samples were found to be so.

Adolescent↗
PubMed1991

[A study of root resorption of deciduous teeth in dogs. Influence of successional tooth germ and occlusal force].

The role of successional tooth germ and occlusal force in root resorption of mandibular second deciduous molars was studied in 24 beagle dogs by means of radiographic and histologic evaluations. 70 days after birth their mandibular right third permanent premolar germs were surgically removed, and in 10 of the dogs the maxillary right and left second deciduous molars were extracted to decrease the occlusal force on the mandibular second deciduous molars. 1) When successional tooth germs were present, whether the occlusal force was normal or decreased, the alveolar bone and deciduous tooth adjacent to the tooth germ were resorbed, accompanied by eruption of the permanent tooth. After the resorption of the deciduous tooth reached half of the root, many odontoclasts were observed in the dental pulp of the deciduous tooth. The root resorption was hastened by internal resorption. 2) When successional tooth germs were removed, whether the occlusal force was normal or decreased, the root resorption was delayed. The resorption from the root surface progressed very slowly, but shortly after this resorption reached the pulp, internal resorption occurred and the deciduous tooth was resorbed in short time. 3) When the occlusal force was decreased, in the deciduous teeth in which successional tooth germs were present, the tooth resorption tended to delay to a later time. However in the deciduous teeth from which the successional tooth germs were removed, the processes of tooth resorption was very different in individuals, the difference between tooth resorption in normal occlusal force and in decreased occlusal force was not clear. 4) In all groups, shallow resorption on the deciduous root surface was observed before the successional tooth started to erupt, and this resorption was apart from the tooth germ. By repeating resorptive periods and resting periods, this resorption progressed according to the increase in age, and in the resting period, resorption was repaired by new deposits of cementum.

Animals↗
PubMed1991

Patient characteristics and treatment variables associated with apical root resorption during orthodontic treatment.

Multivariate analysis of patient characteristics and clinical variables was carried out with the maximum single maxillary incisor apical root resorption for each patient as the dependent variable. Root lengths were measured in standardized intraoral radiographs from 485 consecutively treated patients, 11.5 to 25 years of age. The correlation matrix revealed a complex pattern of positive and negative associations between the six pretreatment and seven treatment variables. Variables found to contribute significantly to apical root resorption were overjet, history of trauma to maxillary incisors before initiation of treatment, time of treatment with rectangular arch wires, time of treatment with Class II elastics, lip/tongue dysfunction, and/or history of finger-sucking habits persisting beyond the age of 7 years, and impacted maxillary canines to be corrected orthodontically. Clinical application of an open activator was significantly correlated with overjet but negatively correlated with apical root resorption, with the use of rectangular arch wires and/or Class II elastics, and with total banding time.

Adolescent↗
PubMed1992

Assessment of external root resorption using digital subtraction radiography.

Digital subtraction radiography was investigated for its capability to detect and quantify experimentally produced external root resorptive defects in teeth. Using a long source to object X-ray technique and E-speed film, serial radiographs of teeth with artificial lesions in a dry human skull (soft tissue simulated) were obtained. Receiver operating characteristic analysis was used to evaluate the diagnostic performance for each imaging system (conventional versus subtraction). To explore the quantitative assessment potential of digital subtraction radiography, images were produced after sequential demineralization by HCl. The acid solution was analyzed for calcium concentration by atomic absorption spectrophotometry. Three-dimensional histogram quantification for each subtracted image was performed. In overall performance for detecting experimentally produced external root resorption, digital subtraction radiography was found to be significantly superior to conventional radiography. In addition, digital subtraction radiography can provide quantification of experimentally produced external root resorptive defects.

Humans↗
PubMed1977

Orthodontic root resorption studied by electron microscopy.

The present study supports previous findings that root resorption takes place simultaneously with and after the elimination of hyalinized tissue. The cementoid layer and the more mature periodontal collagen fibers adjacent to cementum are possible barriers preventing root resorption. The microenvironment around hyalinized tissue is favorable for the introduction of hard-tissue resorbing cells. The findings show that the elimination of hyalinized tissue leads to the removal of the cementoid and the mature collagen thus leaving a raw cemental surface without a barrier. It is therefore hypothesized that such an area is readily attacked by odontoclasts. Once resorption lacunae are established, the cementum is resorbed from the rear as an undermining process. By continued orthodontic force application the resorption process will proceed even after all hyalinized tissue is eliminated. If the orthodontic force is discontinued or falls under a certain level, the resorption lacunae are repaired.

Animals↗
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↗