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PubMed1978

Periodontal and pulpal healing of monkey incisors preserved in tissue culture before replantation.

The effect of delayed replantation and tissue culture as a prevention against root resorption was examined in green Vervet monkeys (Cercopithecus aethiops). Extracted incisors were kept in tissue culture medium (Eagle's medium) for 5--14 days before replantation. The extra-alveolar dry period before tissue culture ranged from to 0 to 60 min. Incisors not subjected to tissue culture served as controls. The animals were sacrificed 8 weeks after replantation. The following histologic parameters were registered for each tooth: surface resorption, inflammatory resorption, replacement resorption (ankylosis), downgrowth of pocket epithelium, and periapical inflammatory changes. The evaluation of the pulp included the extent, recorded in mm, of pulp survival. Histometric evaluation showed that teeth immediately placed in tissue culture medium for 5--14 days showed improved periodontal healing, exhibiting significantly less inflammatory resorption than control teeth immediately replanted. Also the extent of pulp survival was significantly increased in teeth replanted after tissue culture. Teeth bench-dried for 60 min and thereafter placed in tissue culture medium also showed a significant reduction in the amount of inflammatory resorption and increased amount of pulp survival compared with control teeth replanted after the 60-min dry extra-alveolar period. Replacement resorption (ankylosis) was found in all teeth in both groups.

Animals↗
PubMed1992

Odontoclastic resorption at the pulpal surface of coronal dentin prior to the shedding of human deciduous teeth.

Histological and histochemical observations of more than 150 extracted human deciduous teeth revealed that, prior to shedding, odontoclastic resorption as a rule takes place at the pulpal surface of coronal dentin. We also found that this phenomenon occurs in all kinds of deciduous teeth. The process of this internal resorption of coronal dentin of deciduous teeth clearly showed time-related histological changes. During the time the roots were actively being resorbed, the pulpal tissue retained its normal structure. However, when root resorption neared completion, inflammatory cells started to gradually infiltrate into the pulp, and odontoblasts began to degenerate. After that, multinucleate odontoclasts appeared, and resorption proceeded from the predentin to the dentin. The odontoclastic activity was initially detected only on the pulpal surface at the bottom areas of the crown. It gradually spread towards the pulpal horn regions along the wall of the pulp chamber. However, this internal resorption of coronal dentin did not continue until the teeth were finally shed. After the elimination of resorption, the resorbed dentin surface was repaired by a cementum-like deposition or covered with fibrous connective tissue.

Cuspid↗
PubMed2006

Flaws in root resorption assessment algorithms: role of tooth shape.

INTRODUCTION: The purposes of this study were to analyze and critique the mathematical algorithms used in the clinical assessment of root resorption. METHODS: Geometric constructions and derived mathematical expressions were used to investigate the influence of tooth shape on the relationships between tooth, root, and crown lengths and their respective sizes as measured on before and after radiographs. results: The ambiguities of root-loss assessment protocols are demonstrated. CONCLUSIONS: Root resorption assessment algorithms are unsuited for their intended applications.

Algorithms↗
PubMed1999

X-ray diagnosis of impacted upper canines in panoramic radiographs and computed tomographs.

Ten orthodontists were asked to diagnose the number of impacted upper canines and the number of resorbed lateral and/or central incisor roots in 30 panoramic radiographs (P1) from 30 patients. In order to objectify these diagnoses, transversal CT images of all 30 patients were examined in addition. Addition of the recordings in the 30 patients revealed that the 10 orthodontists had diagnosed 350 impacted/displaced canines. On comparison of the P1 and CT results, the latter revealed that, in fact, 390 canines were impacted or displaced, not just 350. Addition of the recordings further showed that, based on P1, the investigators had diagnosed 73 resorptions in the 1,200 incisors examined. However, the CT showed 160 resorptions; this corresponds to a sensitivity value of 45.6%. The CT showed 1,040 incisors with no resorptions, whereas the investigators diagnosed only 925 teeth as not resorbed in the P1. The specificity was thus 88.9%. These results show that, due to their low reliability, panoramic radiographs are not an appropriate means of diagnosing resorptions in front teeth in connection with impacted canines.

Adolescent↗
PubMed1996

Cytodifferentiation of the odontoclast prior to the shedding of human deciduous teeth: an ultrastructural and cytochemical study.

BACKGROUND: In human deciduous teeth, odontoclastic resorption takes place at the pulpal surface of the coronal dentine prior to shedding, and this resorption shows clear time-related histological changes (Sahara et al., 1992). METHODS: Using this phenomenon as an observation system, we examined the cytodifferentiation of human odontoclasts by light and electron microscopy. For a histochemical marker of odontoclast differentiation and function, tartrate-resistant acid phosphatase (TRAP) activity was determined by light and electron microscopic enzyme histochemistry. RESULTS: As root resorption neared completion, TRAP-positive mononuclear cells were initially detected in the pulp chamber. They had abundant mitochondria, small lysosomes, and moderately developed rough endoplasmic reticulum throughout their cytoplasm. In these mononuclear cells, TRAP activity was localized in compartments of the biosynthetic pathway, i.e., in cisternae of the endoplasmic reticulum and Golgi lamellae, as well as small lysosomes. The TRAP-positive mononuclear cells first made contact with the predentine surface by their elongated cellular processes. After attachment, they spread out along the predentine surface and developed specialized membrane structures, clear zones, and ruffled borders. Next, they fused with each other on the predentine surface and formed typical multinucleate odontoclasts. After termination of their resorption function, the odontoclasts lost their ruffled borders and became detached from the resorbed surface. Most of the detached odontoclasts had numerous large pale vacuoles and secondary lysosomes and appeared to be in the process of degeneration. CONCLUSIONS: The present study demonstrates that: (1) odontoclasts differentiated from TRAP-positive mononuclear cells, which presumably originate from circulating progenitor cells, (2) membrane specialization of odontoclasts, i.e., development of a clear zone and ruffled border, is induced following their contact with the resorption surface, (3) multinucleation of odontoclasts takes place only after their attachment to the resorption surface, (4) mature multinucleate odontoclasts can resorb predentine as well as dentine in the same way as osteoclasts resorb bone, and (5) at the end of the resorption, odontoclasts gradually lose their ruffled borders and become detached from the resorbed surface.

Acid Phosphatase↗
PubMed1985

Clinical observations regarding the treatment of traumatically avulsed mature teeth. Part 2.

Two documented cases involving avulsions of an incisor and a cuspid are reported. Long-term observations following replantations indicated factors in addition to those reported in Part 1 of this study. Endodontic metallic implants may retard the intrusive process. A fixed-bridge splint also appears to have retarded the ankylosis phenomenon. The three case reports in the two parts of this study indicated that splint time may not be a critical factor in the prognosis of replanted teeth. Calcium hydroxide failed to prevent early root resorption and eventual ankylosis in an early replantation case; the other two cases, with longer replant time, fared better without calcium hydroxide. Endodontic treatment of avulsed teeth soon after replantation is suggested; a time period of several weeks does not appear critical to the prognosis. Removal of the apical root segment prior to replantation does not appear to affect the replacement root resorption process. The reporting of long-term documented cases should be encouraged in order that replantation techniques may be evaluated.

Adult↗
PubMed2001

Immunolocalization of vacuolar-type H+-ATPase, cathepsin K, matrix metalloproteinase-9, and receptor activator of NFkappaB ligand in odontoclasts during physiological root resorption of human deciduous teeth.

To investigate the cellular mechanisms of physiological root resorption in human deciduous teeth, the authors examined the immunocytochemical localization of vacuolar-type H+-ATPase, a lysosomal cysteine proteinase, cathepsin K, matrix metalloproteinase-9 (MMP-9), and receptor activator of NFKB ligand (RANKL) in odontoclasts. H+-ATPase, cathepsin K, and MMP-9 are the most important enzymes for decalcification of apatite crystals and degradation of type-I collagen. In addition, RANKL is one of the key regulatory molecules in osteoclast formation and functions. Odontoclasts developed extensive ruffled borders and clear zones apposed to the resorbing root dentine surfaces. On immunoelectron microscopy, the expression of vacuolar-type H+-ATPase was detected along the limiting membranes of pale vacuoles and the ruffled border membranes of odontoclasts. Cathepsin K in odontoclasts was localized within pale vacuoles, lysosomes, the extracellular canals of ruffled borders, and the underlying resorbing dentine surfaces. MMP-9 localization in odontoclasts was similar to those of cathepsin K. RANKL was detected in both mononuclear stromal cells and odontoclasts located on resorbing dentine surfaces. These results suggest that (1) odontoclasts are directly involved in decalcification of apatite crystals by active extrusion of proton ions mediated by H+-ATPase and (2) extracellular degradation of dentine type-I collagen by both cathepsin K and MMP-9, and (3) odontoclast differentiation and activity are regulated, at least in part, by RANKL, possibly produced by mononuclear stromal cells and odontoclasts themselves in the resorbing tissues. Thus, the cellular mechanisms of physiological root resorption appear to be quite similar to those of osteoclastic bone resorption.

Carrier Proteins↗
PubMed1981

Hard tissue repair in idiopathic external resorption of teeth.

A histopathological study has been made of 18 erupted and eight unerupted teeth which showed signs of idiopathic external resorption. The findings support the generally accepted theory that osteoclasts are actively involved in the resorptive process, there was no evidence that mononuclear cells were active in this process. The concept that metaplastic hard tissue was deposited on resorbed dentine surfaces, possibly as a means to shield the pulp from the external environment could not be supported from the evidence from this study. When measured, the length of resorption on which metaplastic hard tissues had been deposited, expressed as a percentage of the resorbed area ranged from zero to 69.3 per cent in the 18 erupted teeth. The percentage of metaplastic tissue replacing resorbed tissue in the eight unerupted teeth examined ranged from zero to 55.6 per cent. This study has provided some information on the type of cell responsible for idiopathic external resorption and these findings have been discussed in the light of the results of research of others in this field. The role of metaplastic hard tissue and its function have been evaluated.

Adolescent↗
PubMed1993

Resorption in impacted teeth. A case report.

External resorption of the crown in embedded teeth is uncommon. The authors present a case of an impacted third molar affected by this pathology and review its etiology, pathogenesis, radiological appearance, differential diagnosis and therapy.

Female↗
PubMed1999

Multiple idiopathic resorption in the primary dentition: review of the literature and case report.

Resorption of primary teeth is a normal physiologic process, except when it occurs prematurely. Resorption of permanent teeth is considered abnormal, and multiple etiologic factors have been implicated. A significant number of cases are represented by idiopathic resorption. Multiple idiopathic root resorption stands as a separate physiologic entity that has been described as affecting the entire permanent dentition. Multiple idiopathic resorption of primary teeth has not been previously reported. A case is described and a differential diagnosis is provided. The specific radiographic diagnostic criteria for this condition affecting the primary dentition are outlined.

Child↗
PubMed1991

Prevalence of impacted teeth and associated pathology in middle-aged and older Swedish women.

A representative sample comprising 1418 women from five age strata was examined by means of panoramic radiography. The prevalence of impacted teeth and the frequency and type of pathology associated with the impacted teeth were assessed. About 8% of the total sample had one or more impacted teeth. Among those, pathological conditions were found in 16%. Most were moderate and consisted in most cases of a slightly widened follicle or resorption of the crown. A new examination 12 yr later revealed unchanged conditions in 85% of the cases. The changes that had occurred were generally small.

Adult↗