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A case is presented of an unerupted maxillary second premolar causing the severe resorption of a first molar tooth. This case underlines the need for adequate radiographic evidence before recommending the extraction of teeth for the relief of crowding.
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.
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.
This case report describes an innovative restorative technique using glass ionomer and posterior composite resin materials. It was used to treat a patient with extensive internal resorption of the clinical crown of the maxillary first molar. Although unconventional, this method successfully strengthened and restored the tooth.
Administration of indomethacin inhibited the appearance of osteoclasts and bone resorption induced by experimental tooth movement in rats. Effects were limited to groups injected within 12 h after treatment. Prostaglandin E1 or E2 solutions injected in gingiva lying near the upper first molar caused the appearance of osteoclasts and bone resorption.
Administration of imidazole and verapamil inhibited the appearance of osteoclasts and bone resorption induced by experimental tooth movement in rats. On the other hand, administration of theophylline and ouabain enhanced the appearance of osteoclasts. A mixed solution of DB cyclic AMP and A-23187 injected in gingiva near the orthodontically-treated teeth caused enhancement of the appearance of osteoclasts and bone resorption.
Autotransplantation of teeth has been performed for many years and with varying degrees of success. The present report concerns the long-term results of autotransplantation of 36 teeth with completed root formation. Endodontic treatment was started before or within 12 weeks after transplantation. At the final check-up 32 teeth were present, 24 of them without signs of inflammation, replacement, or internal resorption. Careful radiographic examination during the follow-up period and adequate therapeutic measures with inter alia renewed endodontic treatment are of importance for successful autotransplantation.
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Intracoronal radiolucencies in unerupted teeth are an uncommon radiographic finding; but their early detection and classification allow the most appropriate management protocol to be developed. Early separation of lesions into those that are developmental and remain static and those that are reactive and aggressive is necessary for a controlled outcome. The current paper reviews possible formative mechanisms and describes a case of severe intracoronal resorption resulting in loss of the tooth.
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The present study was carried out to investigate the alveolar bone resorption in the molar tooth region in the rats fed a low calcium diet. Male Wistar rats (70-85g in body weight) were either fed a low calcium diet (0.05% Ca, 0.35% P) or a control diet (0.5% Ca, 0.35% P) by using a pair feeding technique. The rats were sacrificed at intervals of 3, 6, 9 and 20 days during the experimental period. Contact microradiograph of the second molar region of the mandible showed that the cancellus bone as well as the endosteal surface of the cortical bone were progressively resorbed soon after the start of low calcium feeding. At day 9, the amount of bone was reduced to about half of the control rats and 80% of the bone was diminished at day 20. In spite of the severe bone resorption, the alveolar bone proper that surrounds the molar sockets and a few cancellus bone were seen remaining and the occlusal function of the molar tooth seemed to be maintained. These results suggest that the alveolar bone quickly responded to the low calcium diet resulting in bone resorption and that the bone in the supporting tissues of the molar tooth seems to be not affected by the calcium deficiency.
The osteopetrotic (ia) rat was examined as an experimental model for studying the dependence of tooth eruption on bone resorption. In ia rats eruption of incisors and first molars was rare and eruption of second and third molars was reduced and delayed. Autoradiographic studies of 3H-proline incorporation showed that delayed eruption was not due to reduced tooth formation. Microscopic study revealed distortion and failure of posterior growth of the apical ends of incisors, unresorbed bone blocking the eruption pathway for molars, and ankylosis of incisors and first molars to alveolar bone. A reduction in bone resorption, known to be the primary cause of the disease in ia rats, is presumed to be the cause of the delayed or unerupted dentition. The effectiveness of attempts to increase bone resorption in ia rats at an early age by injection of vitamin A and/or parathyroid extract or by parabiotic union with a normal littermate was determined by measuring their effect on the relative size of the tibial marrow cavity. Only parabiosis had a beneficial effect on bone resorption but surgical union could not be performed in animals young enough to affect eruption of incisors and first molars in ia parabionts. These results suggest that parabiotic union of neonatal rats should allow resorption to begin early enough to test the presumed dependence of tooth eruption on bone resorption.
This paper presents ultrastructural features of the contact region between particular tooth germs and Meckel's cartilage prior to, during, and after initial resorption of the perichondral bone and of the cartilage in the cichlids Hemichromis bimaculatus and Astatotilapia burtoni. Imminent resorption opposite such teeth is announced by the presence, in this region, of a particular cell type, considered to be a stage in the cytodifferentiation of osteoclasts. Slightly later, an osteoclast with typical ruffled border is seen to open a fenestra in the perichondral bone which surrounds Meckel's cartilage. Although the action of the osteoclast is directed primarily towards the bone, it may also affect, to a much lesser extent, the underlying uncalcified cartilage. Typically, fibroblast-like cells invade the resorption cavity along with the osteoclast; the tooth germ soon follows. Capillaries are seen to invade the cartilage only at a later stage when a large cavity has been established. It is proposed that the fibroblast-like cells may have a dual function: degradation of cartilage and deposition of new bone. Although these processes are normally limited to the area surrounding tooth germs at specific loci, tooth germs in other positions may sometimes be seen invade the cartilage. They do so either passively, because of the existence of such a cavity, or as a result of their own resorption-inducing activity. Whatever the mechanism, attachment bone is being deposited within the erosion cavity and on the surface of the exposed perichondral bone. The stimuli possibly eliciting resorption of Meckel's cartilage are discussed. It is hypothesized that pressure exerted by the growing tooth germ may stimulate the osteoblasts covering the bone surface and, in this way, provoke osteoclastic bone resorption.
The aim of this clinical and confocal laser scanning microscopic study was to compare the effects of two frequently used archwires on tooth movement and root resorption. A total of 84 premolars in 27 individuals (10 boys, 17 girls, with a mean age of 12.5 years) was moved buccally with an experimental fixed orthodontic appliance. In a split mouth experimental design the premolar on one side was activated with a stainless steel wire with a buccal offset of 1 mm, which was reactivated every four weeks and the contralateral premolar was moved with a superelastic wire with a force plateau of 0.8-1 N. This wire had an initial activation of 4.5 mm and was not reactivated during the 12-week experimental period. At the end of the experimental period the teeth were extracted. Six premolars were used as control teeth and were extracted before the experiment started. Tooth displacement was studied three-dimensionally on dental casts with a co-ordinate measuring machine. The depth, perimeter, area, and volume of the resorption lacunae was measured using three-dimensional digital images made with a confocal laser scanning microscope (CLSM). On these images the resorbed portions of the root surface were 'reconstructed' mathematically. The results show that the teeth activated with the superelastic wire moved significantly more than the teeth with the steel wire during the experimental period. The depth of the resorption lacunae did not differ significantly between the groups; however, perimeter, area, and volume of the resorption lacunae on the teeth of the 'superelastic group' were 140 per cent greater than on the teeth of the 'steel group'. It may be concluded that a greater amount of tooth movement occurred with superelastic wires, offering a force level of 0.8-1 N compared with stainless steel wires, with initially higher but rapidly declining forces in an experimental set up for a period of 12 weeks. The amount of root resorption was significantly larger in the superelastic group.