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A tooth with cervical resorption possibly caused by an internal bleaching technique was treated with calcium hydroxide. This case had characteristics in common with the other seven cases that have been described in the literature. Several possible treatment methods are discussed, along with the speculation that internal bleaching of tetracycline-discolored teeth may lead to cervical resorption.
A commonly recognized dental problem in cats is the resorption of tooth structure and subsequent loss of the tooth. These tooth defects are often very painful, because the sensitive dentin layer is exposed. The destruction of the tooth through odontoclastic resorption is considered a consequence of inflammatory resorption, probably secondary to periodontal inflammation. Because these resorptive lesions are progressive in nature, it is best to stage this progression of resorption in order to address treatment planning. The purpose of this study was to evaluate a group of 58 cats with resorptive lesions to determine the outcome of treatment 6 months or longer after restoration. In 81% of the cats, there was loss of the tooth, evidence of further resorption, or loss of the restoration at one or more resorption sites. Of the 154 teeth restored, only 33% showed no further evidence of loss of tooth structure.
Delayed replantation of an avulsed tooth with an open apex resulted in failure of revascularization, necrosis of the pulp and extensive external root resorption. Removal of the necrotic pulp and repeated intra-canal dressings of calcium hydroxide over a three year period arrested the inflammatory resorptive process. The process was replaced by replacement resorption leading to ankylosis and infra-occlusion of the affected tooth. As the tooth was asymptomatic, it was retained in the arch to act as a space maintainer. To improve aesthetics, the crown was recontoured using a light-cured resin.
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Matrix metalloproteinases are involved in the regulation of bone remodeling. The hypothesis that matrix metalloproteinase inhibitors may be useful for experimentally limiting orthodontic tooth movement, a process involving perturbations of normal bone remodeling, was tested. General matrix metalloproteinase inhibitors limited the resorption of bone slices by mouse marrow cultures stimulated by calcitriol, parathyroid hormone, and basic-fibroblast growth factor. Pre-coating dentin slices with short arginine-glycine aspartic acid (RGD) peptides, but not arginine-glycine-glutamic acid (RGE) controls, restored bone resorption in the presence of matrix metalloproteinase inhibitors. Orthodontic tooth movement was inhibited by local delivery of Ilomastat, a general matrix metalloproteinase inhibitor, with the use of ethylene-vinyl-acetate (ELVAX) 40, a non-biodegradable, non-inflammatory sustained-release polymer. This study shows that orthodontic tooth movement can be inhibited with the use of matrix metalloproteinase inhibitors, and suggests a mechanistic link between matrix metalloproteinase activity and the production of RGD peptides.
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Possible modifications in orthodontic tooth movement (OTM) and root resorption as a result of local injections of prostaglandin E2 (PGE2) alone and with calcium gluconate (Ca) formed the aim of the present study. Twenty-four 8-week-old male Wistar rats were selected and randomly divided into three groups of eight. Both quadrants of the upper jaws of the first group of animals were used; therefore this group comprised two groups: control and normal. The upper left first molars of these eight animals were not placed under orthodontic force and received no injection, to serve as the normal group, considered for root resorption comparison only. The control group had localized submucosal injections of normal saline on the buccal side of the upper right first molar. In the third group, 0.1 ml of 1 mg/ml PGE2 was injected at the same site and the fourth group received an intraperitoneal injection of 200 mg/kg Ca (10%) in addition to the PGE2. All the injections were performed on days 0 and 7. The orthodontic appliance consisted of a closed coil spring ligated to the upper right first molar and incisor, exerting a force of 60 g during the 21-day experimental period, after which the animals were sacrificed. Palatal halves were removed for histological examination and for calculation of the amount of root resorption. Statistical analysis of data showed a significant (P < 0.05) acceleration in OTM after PGE2 injection compared with the control group. The addition of Ca reduced OTM but a significant increase (P< 0.05) was still recorded. A significant difference (P < 0.05) in root resorption was only observed between the PGE2 and normal groups. The findings show the importance of calcium ions working in association with PGE2 in stabilizing root resorption while significantly increasing OTM.
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Clinical orthodontists frequently reactivate appliances following decay. Studies of tooth movement and tissue responses following reactivations indicate that linear tooth movement and rapid recruitment of osteoclasts can be achieved if reactivation is timed to coincide with the latter part of the bone remodeling cycle initiated by the first activation. Both can be delayed if reactivations are timed for the early part of the previous cycle. The objective of this study was to examine tooth movement, root resorption, and osteoclast recruitment following appliance reactivation after the first activation had decayed. Bilateral orthodontic appliances were activated with 40 cN in 144 rats to mesially tip the maxillary molars. After 16 days, rats were randomized into two groups of 72. In group 1, appliances were reactivated in precisely the same manner as the first activation. In group 2, appliances were sham-reactivated. Rats were sacrificed at 1, 3, 5, 7, 10, and 14 days. Orthodontic movement was measured cephalometrically; changes in osteoclasts and root resorption were assessed at both compression and tension sites histomorphometrically; tartrate-resistant acid phosphatase (TRAP) was measured in alveolar bone and serum biochemically. Orthodontic tooth movement was linear in group 1, but osteoclasts required 3 to 5 days to appear. There were no group- or time-related differences in root resorption. Bone TRAP levels were elevated in both groups but dropped significantly (p<0.01) in group 2 at day 7. Appliance reactivations that followed decay of the first activation produced efficient tooth movement without increased risk of root resorption, but these changes were not accompanied by rapid osteoclast recruitment at compression sites. Timing appliance reactivations for the latter portion of the previous bone remodeling cycle could have significant clinical advantages because the delay period seen in tooth movement following a single activation or short-term reactivation can be avoided.
Twenty Sprague-Dawley rats weighing 280-300 g were divided into two groups of ten animals each. They were treated by daily submucosal injections of 50 micrograms prostaglandin E2 (PGE2) per kilogram body weight into the region below the apex of the left first maxillary molar (experimental), or vehicle into the region below the apex of the right first molar (control), for a period of 5 days. The animals of the first group were sacrificed immediately following the treatment period, while those of the second group were sacrificed 5 days after the treatment period. Twenty-two hours prior to sacrifice, a piece of latex orthodontic elastic was secured to the adjacent area between the first and second maxillary molars of both sides of each rat by using two mosquito hemostats. The periodontal ligament (PDL) mesial to the mesiobuccal root of the first maxillary molar was assayed for changes in PDL cell factors. The results showed that immediately following the 5-day treatment period the left PDL had a significant decrease in the total number of fibroblasts and a significant increase in the total number of both osteoclasts and nuclei per osteoclast, while no significant changes in the osteoblasts when compared with those of the right control PDL. The left PDL of animals which were sacrificed 5 days after the treatment period revealed a significant decrease in the number of total fibroblasts and only a slight decrease in both numbers of total osteoclasts and total nuclei per osteoclast, but again no significant changes in osteoblasts when compared with those of the right control PDL.(ABSTRACT TRUNCATED AT 250 WORDS)
The purpose of orthodontic treatment is to move teeth as efficiently as possible with least damage to teeth and their supporting tissues. Root resorption may occur as an unwanted side effect and may in some instances jeopardize an otherwise successful treatment. The general aim of this series of clinical investigations was to study the association between applied force, achieved tooth movement and related root resorptions. In 144 adolescents, the maxillary first or second premolar was buccally moved with a fixed orthodontic appliance. The variables studied were duration, magnitude and type of force. Moreover, both the occurrence of orthodontically induced root resorptions and the reparative potential were investigated in histological preparations of the teeth. When a continuous force of a clinically relevant magnitude (50 cN approximately 50 g) was applied, tooth movement increased gradually over time. Root resorptions were recorded in all test teeth but 4 (93%). After 3 weeks a few teeth revealed root resorptions extending half way to the pulp or more in the apical third of the root. No association was found between root resorptions and tooth movement. Doubling the force magnitude (100 cN approximately 100 g) affected neither the tooth movement nor the severity of root resorptions. However, when the force was increased 4 times (200 cN approximately 200 g), tooth movement increased 50% but still with no significant increase in the occurrence or severity of root resorptions. Tooth movement was achieved more efficiently with a continuous force than with an interrupted type of force of the same magnitude (50 cN). Root resorptions, though, did not seem to be affected differently by the two types of forces. Reduction of all types of applied forces was considerable, about 25-30%, already within one week. Repair with secondary cementum was recorded almost 3 times more often after 8 weeks (75%) of retention than after 1 week (28%). Irrespective of magnitude and type of force, large individual variations were observed regarding tooth movements and root resorptions as well as their reparative potential. The possible clinical consequences of the results obtained are discussed with regard to cost-benefit effects, convenience to the patient and risk of complications.
Some types of tooth root resorption respond favourably to endodontic treatment. Sometimes compromising factors demand particular treatment approaches and techniques. These will be described, in connection with their genesis.
This article reports a case of a maxillary second premolar which on presentation was partially erupted, and which resisted attempts at orthodontic extrusion. The crown of the tooth was eventually restored using an adhesive composite onlay technique. The patient subsequently complained of pain and the root of the tooth showed radiographic evidence of resorption. The root of the extracted tooth had a vital pulp but massive external resorption was evident, with repair with bone-like material.