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Root Resorption (root + resorption)
Kinds of Root Resorption Selected AbstractsRoot resorption in retained deciduous canine and molar teeth without permanent successors in patients with severe hypodontiaINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 3 2001K. Haselden Aims. The ability to predict the morbidity of retained deciduous teeth with no permanent successors, a characteristic of hypodontia, would be of considerable value in treatment planning, but is hampered by lack of data. Methods. This problem was studied using 356 orthopantomogram radiographs (OPGs) from the records of 249 patients who had attended a specialist hypodontia clinic, and had retained deciduous teeth with no permanent successors. Due to their clinical importance, canine and molar teeth were chosen for examination. Resorption was assessed subjectively by three experienced clinicians. Results. Un-weighted Kappa values for reproducibility were > 0·8, and for inter-observer error 0·60,0·83. Gender related differences were minimal. Regardless of gender or radiographic age, the lower canines appear to show the least amount of resorption and the upper first molars the most. The upper and lower second molars have particularly unpredictable life spans. Whilst the lower first molars have a predictable life span that is poor, the life span for the upper first molars is slightly worse. Conclusions. Lower canines have a predictable life span that appears to be good, as do upper canines, but of lesser duration than lower canines. Molars have poorer and less predictable life spans. [source] Dental root resorption and repair: histology and histometry during physiological drift of rat molarsJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2003Ryusei Kimura Objective:, The process of dental root resorption and subsequent cementum regeneration has not been sufficiently elucidated. This study aimed to examine the process of the root resorption and cementum regeneration during physiological tooth drift using a rat model, and to evaluate this experimental model. Methods:, Distal roots in mandibular first molars and the surrounding periodontal tissues were investigated with light and electron microscopy. The light microscopic approach included histochemical and histometric analyses utilizing the tartrate-resistant acid phosphatase (TRAP) reaction. Results:, Root resorption was observed in the distal side of the roots and was most active in 5- to 6-week-old rats, and gradually decreased hereafter. An increase in the number of TRAP-positive mononuclear cells, which seemed to be odontoclast precursor cells, preceded the increase in the number of odontoclasts. Root resorption was transient, and was followed by the new formation of acellular extrinsic fiber cementum accompanied with only a slight inflammation, and therefore classified as external surface resorption. Preparation for new cementum started adjacent to the resorption areas when root resorption was most active. Conclusions:, The root resorption during drift in rats is transient and followed by acellular extrinsic fiber cementum regeneration. Cellular kinetics suggested that odontoclast precursor cells are supplied as mononuclear cells from vascular spaces. [source] Orthodontic rehabilitation for anterior teeth lost due to trauma with crowding malocclusionDENTAL TRAUMATOLOGY, Issue 4 2010Masayoshi Kawakami The central incisors were immediately replaced and fixed with application of a semi-rigid splint for 12 days, then endodontically treated. Severe root resorption and degeneration of periodontal tissue were noted after 4 years and the teeth were extracted, while the patient had also developed maxillary protrusion with severe crowding in the lower arch. The treatment objectives were to close the spaces by mesial movement of the buccal segment in the upper arch and eliminate crowding by extraction of the lower bicuspids. Favorable occlusion was achieved as was substitution with the lateral incisors for the lost central teeth. [source] An evidence-based assessment of the clinical guidelines for replanted avulsed teeth.DENTAL TRAUMATOLOGY, Issue 2 2009Part II: prescription of systemic antibiotics The principles of evidence-based dentistry can be used to assess whether this is the best approach based on currently-available evidence. The objective of this study was to use the principles of evidence-based dentistry to answer the PICO question: (P) for a replanted avulsed permanent tooth, (I) is prescribing SAT, (C) compared with not prescribing SAT, (O) associated with an increased likelihood of successful periodontal healing after tooth replantation? Materials and methods:, A literature search was performed across four internet databases (Ovid Medline, Cochrane Library, PubMed, ISI Web of Science), for relevant citations (n = 35 702). Limiting citations to those in English and removing duplicates produced a set of titles (n = 14 742) that were sieved according to evidence-based dentistry principles. Relevant titles were selected for abstract assessment (n = 782), identifying papers for examination (n = 74). Inclusion criteria were applied and three papers (326 total teeth) met the final criteria for meta-analysis. Results:, Meta-analyses found no statistically significant difference between prescribing or not prescribing antibiotics for acceptable periodontal healing without progressive root resorption (common odds ratio = 0.90, SE = 0.29, 95% confidence intervals = 0.51,1.58). Conclusion:, The evidence for an association between prescribing SAT and an increased likelihood of acceptable periodontal healing outcome is inconclusive. This investigation of antibiotic use as defined in the clinical guidelines indicates there is inconclusive clinical evidence from studies of replanted avulsed human teeth to either contradict or support the guideline. Pending future research to the contrary, dentists are recommended to follow current guidelines in prescribing SAT when replanting avulsed teeth. [source] Effect of root surface treatment with propolis and fluoride in delayed tooth replantation in ratsDENTAL TRAUMATOLOGY, Issue 6 2008Jéssica Lemos Gulinelli Nevertheless, an extended extraoral period damages the periodontal ligament and results in external root resorption. The purpose of this study was to assess by histologic and histometric analysis, the influence of propolis 15% (natural resinous substance collected by Apis mellifera bees from various plants) and the fluoride solution used as root surface treatment on the healing process after delayed tooth replantation. Thirty Wistar (Rattus norvegicus albinus) rats were submitted to extraction of their upper right incisor. The teeth were maintained in a dry environment for 60 min. After this, the pulp was extirpated and the papilla, enamel organ and periodontal ligament were removed with scalpel. The teeth were divided into three experimental groups: Group I , teeth immersed in 20 ml of physiologic saline; Group II , teeth immersed in 20 ml of 2% acidulated phosphate sodium fluoride; Group III , teeth immersed in 20 ml of 15% propolis. After 10 min of immersion in the solutions, the root canals were dried and filled with calcium hydroxide paste and the teeth were replanted. The animals were euthanized 60 days after replantation. The results showed that similar external root resorption was seen in the propolis and fluoride groups. Teeth treated with physiologic saline tended to have more inflammatory root resorption compared with those treated with fluoride or propolis. However, the comparative analysis did not reveal statistically significant differences (P > 0.05) between the treatment modalities when used for delayed tooth replantation. [source] Pulp and periodontal healing of laterally luxated permanent teeth: results after 4 yearsDENTAL TRAUMATOLOGY, Issue 6 2008Elena C. Ferrazzini Pozzi Material and methods:, Patients presenting with lateral luxation of permanent teeth during 2001,2002 were enrolled in this clinical study. Laterally luxated teeth were repositioned and splinted with a TTS/composite resin splint for 4 weeks. Immediate (prophylactic) root-canal treatment was performed in severely luxated teeth with radiographically closed apices. All patients received tetracycline for 10 days. Re-examinations were performed after 1, 2, 3, 6, 12 and 48 months. Results:, All 47 laterally luxated permanent teeth that could be followed over the entire study period survived. In 10 teeth (21.3%), a prophylactic root-canal treatment was performed within 2 weeks following injury. The remaining 37 teeth showed the following characteristics at the 4-year re-examination: 19 teeth (51.4%) had pulp survival (no clinical or radiographic signs or symptoms), nine teeth (24.3%) presented with pulp canal calcification, and pulp necrosis was seen in another nine teeth (24.3%), within the first year after trauma. None of the teeth with a radiographically open apex at the time of lateral luxation showed complications. External root resorption was only seen in one tooth. Conclusions:, Laterally luxated permanent teeth with incomplete root formation have a good prognosis, with all teeth surviving in this study. The most frequent complication was pulp necrosis that was only seen in teeth with closed apices. [source] Rapidly progressive internal root resorption: a case reportDENTAL TRAUMATOLOGY, Issue 5 2008David Keinan Usually the process is asymptomatic and diagnosed upon routine radiographic examination. This case report presents a rapid progression of internal resorption related directly to traumatic injury. A 16-year-old female arrived at the emergency room after a mild extrusion of the mandibular incisors. The initial treatment included repositioning and splinting of the teeth. Radiographs performed at repositioning and splinting demonstrated normal configuration of the incisor's roots. Ten months later progressive internal resorption of the left mandibular first incisor was diagnosed. While treating this tooth similar process was detected in the right mandibular second incisor and in the mandibular left second incisor. The lower right first incisor reacted inconsistently to vitality test. As a result of the severe and rapidly progressive nature of the process, root canal treatments were performed in all lower incisors. The follow-up radiographs demonstrate arrest of the internal resorption process. [source] An investigation into dentists' management methods of dental trauma to maxillary permanent incisors in Victoria, AustraliaDENTAL TRAUMATOLOGY, Issue 4 2008Thai Yeng To a large extent, the management actions of the dentists involved will determine the clinical outcome and, in turn, these actions will be related to their levels of knowledge. The aim of this study was to investigate dentists' knowledge of managing traumatic injuries to maxillary permanent incisors in children. A self-completion questionnaire containing 19 questions on management methods of treating dental trauma was mailed to 693 dentists in Victoria, Australia. The response rate achieved was 61%. This survey found that some of the respondents had adequate management knowledge for the different types of traumatic injuries, while others did not have the correct information. Approximately half the dentists considered milk as the preferred extraoral storage medium of choice for avulsed teeth and a period of 7,10 days splinting after replantation. A large proportion of dentists showed inadequate knowledge with regard to understanding the biological mechanisms causing replacement root resorption (61%) and external inflammatory root resorption (74%). Overall, the respondents to this survey demonstrated only a moderate level of knowledge in management of traumatic injuries to maxillary permanent incisors in children. Continuing professional development programmes may be a means of improving this deficient knowledge base. [source] Mechanical removal of necrotic periodontal ligament by either Robinson bristle brush with pumice or scalpel blade.DENTAL TRAUMATOLOGY, Issue 6 2007Histomorphometric analysis, scanning electron microscopy Abstract,,, One of the important factors accounting for successful delayed replantation of avulsed teeth is seemingly the type of root surface treatment. Removal of necrotic cemental periodontal ligament remnants may prevent the occurrence of external root resorption, which is the major cause of loss of teeth replanted in such conditions. The purpose of this study was to compare the efficacy of two mechanical techniques for removal of root-adhered periodontal ligament. Preservation or removal of the cementum layer concomitantly with these procedures was also assessed. Forty-five roots of healthy premolars extracted for orthodontic purposes were selected. After extraction, the teeth were kept dry at room temperature for 1 h and then immersed in saline for rehydration for an additional 10 min. Thereafter, the roots were assigned to three groups, as follows: group 1 (control) - the cemental periodontal ligament was preserved; group 2 - removal of the periodontal ligament by scraping root surface with a scalpel blade (SBS); group 3 - periodontal ligament remnants were removed using a Robinson bristle brush at low-speed with pumice/water slurry (RBP). The specimens were analysed histomorphometrically and examined by scanning electron microscopy. The quantitative and qualitative analyses of the results showed that the RBP technique was significantly more effective than the SBS technique for removal of the periodontal ligament remnants adhered to root surface. Both techniques preserved the cementum layer. [source] Evaluation of intruded primary incisorsDENTAL TRAUMATOLOGY, Issue 3 2005Juliana Oliveira Gondim Abstract,,, Tooth intrusion consists of the displacement of the tooth into its alveolus and is the most common trauma during early infancy. This work aims to evaluate the aspects related to tooth intrusion in primary teeth by monitoring 16 patients (22 teeth) for a period between 3 and 36 months. Of the patients who suffered from tooth intrusion, 56.25% were male and 91% of the intruding teeth were upper central incisors. In all cases the treatment indicated was to await spontaneous re-eruption: total re-eruption occurred in 42.5% of cases, partial re-eruption in 47% of cases and in 10.5% there was no re-eruption. Twenty-three percentage of the teeth suffered necrosis, 33% suffered internal or external root resorption and none suffered root canal obliteration. Fifty-seven percentage indicated healthy pulps independent of degree of re-eruption. [source] Federal University of Santa Catarina follow-up management routine for traumatized primary teeth , part 1DENTAL TRAUMATOLOGY, Issue 6 2004Mariane Cardoso Abstract,,, The objective of this study was to verify if the follow-up management routine of traumatized primary teeth set up by Federal University of Santa Catarina, which performs clinical and radiographic assessments (15 and 45 days; 4, 8 and 12 months) after the oral trauma, enabled an early diagnosis of sequelae which would indicate the need for endodontic intervention, as well as the influence a type of trauma and the child's age could have in the severity of the sequelae. In this study 52 sets of records were used of patients being seen in the last 6 months, with a total of 70 teeth that were receiving follow-up treatment. Patients returned for regular visits set up by the management routine, where clinical and radiographic examinations were performed to check for sequelae, which justified endodontic intervention. Mobility (51.2%) and crown discoloration (25.6%) were the most common sequelae found in the patient's first appointment. In the follow-up visits, replacement root resorption (22.5%) was the second most common sequela found, suggesting endodontic intervention. No significant association was found between severe sequelae, types of trauma and a child's age (,2 = 0.3, P = 0,8613). During the intervals of the follow-up visits, it was noticed that between 46 days and 8 months a higher number of sequelae were diagnosed (P < 0.05). The diagnosis of sequelae such inflammatory and replacement root resorption, which can lead to an early loss of a primary tooth, are frequent and that the interval between the follow-up visits has to be changed, suggesting the setting up of management routine 2. The study also concluded that the type of trauma and the child's age are not fundamental factors in the diagnosis of severe sequelae. [source] Influence of surgical repositioning of mature permanent dog teeth following experimental intrusion: a histologic assessmentDENTAL TRAUMATOLOGY, Issue 6 2002R. F. Cunha Abstract,,, The aim of this study was to evaluate, through histologic examination, the effect of surgical repositioning of intruded dog teeth upon the pulpal and surrounding tissues. Thirty teeth in 10 adult dogs, aged 2,3 years, were used. Fifteen teeth were intruded, surgically repositioned and fixed using orthodontics wire, composite resin, and enamel acid conditioning. All these teeth served as the experimental group. The remaining intruded teeth were not treated (control group). The animals were sacrificed to allow observations at 7, 15, and 30 post-operative days. The maxillary and mandibular archs were removed and processed for histologic exam. Based on the methodology and observed results, we concluded that: pulpal necrosis, external root resorption and ankylosis were common sequelae to severe traumatic intrusion; a careful immediate surgical repositioning of severed intruded permanent tooth with complete root formation has many advantages with few disadvantages. [source] Effects and distribution of the enamel matrix derivative Emdogain® in the periodontal tissues of rat molars transplanted to the abdominal wallDENTAL TRAUMATOLOGY, Issue 1 2002Yoshioki Hamamoto Abstract , The enamel matrix derivative Emdogain® (EMD) has been found to promote regeneration of lost periodontal tissues. We have studied the effects and distribution of EMD in the periodontal tissues of maxillary rat molars transplanted to a subcutaneous position in the abdominal wall. The molars were transplanted with or without EMD either immediately after extraction or after drying for 30 min. After 2 days, 1, 2 or 4 weeks the rats were killed and the teeth were examined by means of light microscopy and immunohistochemistry with anti-amelogenin antibodies. Teeth transplanted immediately after extraction showed formation of alveolar bone separated from the dental roots by a periodontal space, regardless of the use of EMD. Among the teeth that were transplanted with EMD after drying for 30 min, new alveolar bone was formed in five out of eight teeth after 2 and 4 weeks. None of the teeth that were dried for 30 min and transplanted without EMD showed alveolar bone formation. Only one tooth transplanted with EMD showed root resorption after drying, while resorption was noted in all teeth transplanted without EMD. All teeth that were transplanted with EMD and none of the teeth that were transplanted without EMD showed an immunohistochemical reaction for amelogenin. After 2 days, amelogenin was precipitated on all surfaces exposed at the transplantation procedure. Later, the immunoreactive material was redistributed to cells at the root surface, where it was still demonstrable after 4 weeks. In conclusion, EMD is accumulated in cells at the root surface and promotes regeneration of the periodontal tissues of the transplanted teeth. It also seems to promote healing of root resorption. [source] Periodontal response to two intracanal medicaments in replanted monkey incisorsDENTAL TRAUMATOLOGY, Issue 6 2001Y. L. Thong Abstract , Intracanal medicaments are recommended for use in replanted teeth to inhibit inflammatory root resorption. This study compared the effect of calcium hydroxide (Pulpdent®) and a corticosteroid-antibiotic paste (Ledermix®) on periodontal healing and root resorption following replantation. Incisors of eight Macaca fascicularis monkeys were extracted, stored dry for 15 min and replanted. After 11 days, root canals in two adjacent maxillary incisors were treated with one medicament and contralateral incisors with the other medicament, or left as untreated controls. Animals were sacrificed 8 weeks later and the teeth prepared for histomorphometric evaluation of periodontal ligament inflammation and root resorption. Periodontal ligament inflammation and inflammatory root resorption were markedly inhibited by both calcium hydroxide and corticosteroid-antibiotic relative to untreated controls. Replacement resorption was lowest in the corticosteroid-antibiotic group, and significantly (P<0.05) more normal periodontal ligament was present in this group (79.6%) than in calcium hydroxide and control groups (64.6% and 62.7%, respectively). Treatment with the corticosteroid-antibiotic inhibited inflammatory resorption and was slightly more effective than calcium hydroxide in producing a periodontal healing response. [source] Factors affecting the time of onset of resorption in avulsed and replanted incisor teeth in childrenDENTAL TRAUMATOLOGY, Issue 5 2001M. Donaldson Abstract , Resorption is the main reason for loss of replanted teeth. The outcome examined in this study is the timing of the onset of resorption. The effect of dichotomised dry and wet time intervals as well as the presence of additional crown damage and of contamination were determined. Of 84 replanted teeth, 67.5% developed resorptions. Twenty-eight had detectable additional crown damage with a more rapid onset being seen in these cases (P=0.009). The critical limit for dry time was 15 min (P=0.038) and significant differences persisted for greater limits also. Serial analysis of the association between the time of onset of root resorption and dichotomised wet time variables failed to yield any significant associations. There was visible contamination detected in 32 teeth and these exhibited a more rapid onset of resorption than the other cases (P=0.030). Teeth with inflammatory root resorption (12.8%) had a more rapid onset of resorption than those that developed replacement resorption (54.7%) (P<0.001). It is concluded that the risk of early resorption is increased in teeth that have additional damage or have contamination, or are kept in dry conditions for longer than 15 min. [source] Hypothermic insult to the periodontium: a model for the study of aseptic tooth resorptionDENTAL TRAUMATOLOGY, Issue 1 2000C. W. Dreyer Abstract , The aim of the current investigation was to define an animal model for the study of hard tissue resorption by examining the responses of the periodontal ligament (PDL) to both single and multiple episodes of hypothermic injury to the crowns of rat teeth. A group of 12 male rats weighing 200,250 g were anesthetized, and pellets of dry ice (CO2) were applied once to the crowns of the right first maxillary molars for continuous periods of 10 or 20 min. Animals were sacrificed at 2, 7, 14 and 28 days and tissues were processed for routine histological examination. A second group of eight animals and a third group of 12 animals were subjected to three applications of dry ice over a period of 1 week and sacrificed at 2 and 14 days respectively after the final application. In addition to thermal insult, the periodontium of teeth from a fourth group of six rats was subjected to mechanical trauma. Examination of the sections from the group undergoing a single freezing episode revealed that, by 1 week, shallow resorption lacunae had appeared on the root surface. These became more extensive after 14 days. At the same time hyaline degeneration was evident in the PDL. Within this group, teeth subjected to the longer 20-min application times generally showed more extensive injuries. By 28 days, evidence of repair was observed with reparative cementum beginning to line the resorption lacunae in the root dentin. Sections from animals subjected to multiple episodes of thermal trauma and those subjected to additional mechanical insult showed more extensive external root resorption than those from single-injury animals. It was concluded that low temperature stimuli applied to the crowns of rat molars were capable of eliciting a sterile degenerative response in the PDL which, in turn, resulted in external root resorption. Furthermore, the degree of this tissue injury was commensurate with the duration and number of exposures to the trauma. The results also indicated that progression of the resorptive process required periodic exposure to the injury, in the absence of which repair to the damaged root occurred. [source] Diagnostic accuracy of digitized periapical radiographs validated against micro-computed tomography scanning in evaluating orthodontically induced apical root resorptionEUROPEAN JOURNAL OF ORAL SCIENCES, Issue 5 2008Alexander Dudic The aim of this study was to validate the use of digitized periapical radiographs in evaluating orthodontically induced apical root resorption against micro-computed tomography (micro-CT) scanning as a criterion standard test. In a standardized experimental protocol, 29 premolars in 16 subjects were tipped buccally for 8 wk. Nineteen contralateral premolars not subjected to orthodontic movement served as controls. Standardized periapical radiographs were taken before and after the experimental period (Rx method). These teeth were extracted and scanned using a micro-CT technique with a 9 ,m resolution. Two calibrated examiners assessed blindly the presence or absence of apical root resorption on digitized radiographs and three-dimensional reconstructions of the scans. Significant differences were detected between the orthodontically moved teeth and controls: 86% of the orthodontically moved teeth and 21% of the control teeth showed apical root resorption when using micro-CT as a validation method. A total of 55% of the experimental teeth and 5% of the control teeth showed resorption when assessed using Rx method. The Rx method showed a specificity of 78% and a sensitivity of 44%, which means that less than half of the cases with root resorption identified using a CT scanner were identified by radiography. Nearly all the orthodontically moved teeth showed apical root resorption. Apical root resorption may be underestimated when evaluated using digitized periapical radiographs. [source] Accuracy of an electronic apex locator in primary teeth with root resorptionINTERNATIONAL ENDODONTIC JOURNAL, Issue 2 2009O. Angwaravong Abstract Aim, To evaluate whether root resorption of primary molar teeth affects the accuracy of the Root ZX apex locator and to compare the Root ZX at different meter readings with direct canal measurement. Methodology, Sixty extracted primary molar teeth with root resorption affecting one sixth to one third of root length were used. The teeth were embedded in an alginate model. A K-type file was used in association with a Root ZX apex locator to measure canal length. Measurements were recorded using the Root ZX meter reading ,Apex' and ,0.5 bar'. Actual tooth length was measured with a K-file to the major foramen. All measurements were read under a stereomicroscope at 15× magnification. The deviation of the Root ZX measurement from the actual canal length was determined. Results, Mean differences between Root ZX length meter reading ,Apex' and actual length were 0.01 ± 0.23 mm whereas mean differences between Root ZX length meter reading ,0.5 bar' and actual length were ,0.33 ± 0.30 mm. The Root ZX was 96.7% accurate to within ± 0.5 mm of the apical foramen when compared with the actual canal length of primary molars with root resorption. Conclusions, Using a criterion of ± 0.5 mm, the accuracy of the Root ZX was high and not affected by root resorption. When compared with direct canal measurement, the error in locating the apical foramen was smaller with measurement at meter reading ,Apex' than meter reading ,0.5 bar'. [source] The effect of mineral trioxide aggregate on the apexification and periapical healing of teeth with incomplete root formationINTERNATIONAL ENDODONTIC JOURNAL, Issue 1 2006W. T. Felippe Abstract Aim, To evaluate the influence of mineral trioxide aggregate (MTA) on apexification and periapical healing of teeth in dogs with incomplete root formation and previously contaminated canals and to verify the necessity of employing calcium hydroxide paste before using MTA. Methodology, Twenty premolars from two 6-month old dogs were used. After access to the root canals and complete removal of the pulp, the canal systems remained exposed to the oral environment for 2 weeks. Canal preparation was then carried out using Hedström files, under irrigation with 1% sodium hypochlorite, 1 mm short of the radiographic apex. After drying, the canals of two premolars in each dog were left empty (control group). The other eight teeth in each animal were divided into two experimental groups. The apical thirds of the canals of group 1 were filled with MTA. In the teeth of group 2, the canals were dressed with a calcium hydroxide,propylene glycol paste. After 1 week, the paste was removed and the apical third was filled with MTA. All teeth were restored with reinforced zinc oxide cement (IRM) and amalgam. The animals were killed 5 months later, and blocks of the teeth and surrounding tissues were submitted to histological processing. The sections were studied to evaluate seven parameters: formation of an apical calcified tissue barrier, level of barrier formation, inflammatory reaction, bone and root resorption, MTA extrusion, and microorganisms. Results of experimental groups were analysed by Wilcoxon's nonparametric tests and by the test of proportions. The critical value of statistical significance was 5%. Results, Significant differences (P < 0.05) were found in relation to the position of barrier formation and MTA extrusion. The barrier was formed in the interior of the canal in 69.2% of roots from MTA group only. In group 2, it was formed beyond the limits of the canal walls in 75% of the roots. MTA extrusion occurred mainly in roots from group 2. There was similarity between the groups for the other parameters. Conclusions, Mineral trioxide aggregate used after root canal preparation favoured the occurrence of the apexification and periapical healing. The initial use of calcium hydroxide paste was not necessary for apexification to occur, and has shown to be strongly related to the extrusion of MTA and formation of barriers beyond the limits of the root canal walls. [source] The effect of the renewal of calcium hydroxide paste on the apexification and periapical healing of teeth with incomplete root formationINTERNATIONAL ENDODONTIC JOURNAL, Issue 7 2005M. C. S. Felippe Abstract Aim, To evaluate the influence of renewing calcium hydroxide paste on apexification and periapical healing of teeth in dogs with incomplete root formation and previously contaminated canals. Methodology, Forty premolars from four 6-month-old dogs were used. After access to the root canals and complete removal of the pulp, the canal systems remained exposed to the oral environment for 2 weeks. Canal preparation was then carried out using Hedströem files, under irrigation with 1% sodium hypochlorite, 1 mm short of the radiographic apex. After drying, the canals of one premolar in each dog were left empty (group 4-control), and those of the other nine teeth in each animal were filled with a calcium hydroxide-propylene glycol paste. All teeth were restored with reinforced zinc oxide cement (IRM) or IRM and amalgam (group 4). The paste was renewed and the teeth restored again 1 week later. Then, the nine teeth in each animal were divided into three experimental groups: group 1 , paste not changed; group 2 , paste renewed every 4 weeks for 5 months; and group 3 , paste renewed after 3 months had elapsed. The teeth were restored with IRM and amalgam (groups 1 and 3) or IRM (group 2). The animals were killed 5 months later, and blocks of the teeth and surrounding tissues were submitted to histological processing. The sections were studied to evaluate six parameters: apical calcified tissue barrier, inflammatory reaction, bone and root resorption, paste extrusion and microorganisms. Results of experimental groups were analysed by Kruskal,Wallis nonparametric tests and by the test of proportions. The critical value of statistical significance was 5%. Results, Significant differences (P < 0.05) were found in relation to the presence of bone resorption and paste in the periradicular area, the formation of a calcified tissue barrier at the apex, and the intensity of the apical inflammatory reaction. Bone resorption was more evident in group 1 (medicament not changed), and the presence of paste in the periodontal tissues was more common in groups 2 and 3. Renewal of the paste reduced the intensity of the inflammatory reaction (groups 2 and 3), but the formation of apical calcified tissue was more noticeable in the teeth where the paste had not been renewed. Conclusions, Replacement of calcium hydroxide paste was not necessary for apexification to occur, however, it did reduce significantly the intensity of the inflammatory process. Monthly renewal of calcium hydroxide paste reduced significantly the occurrence of apexification. [source] Internal apical resorption and its correlation with the type of apical lesionINTERNATIONAL ENDODONTIC JOURNAL, Issue 11 2004F. V. Vier Abstract Aim, To determine the presence of various periapical pathologies and their association with the presence and extent of internal apical inflammatory root resorption in human teeth. Methodology, A total of 75 root apices from extracted teeth with periapical lesions were examined. Semi-serial sections of soft tissue lesions were stained with HE. The lesions were classified as non-cystic or cystic, and according to the degree of abscess severity: 0, 1, 2 or 3. The apices were reduced to 3 mm in length and longitudinally cut so that the internal aspect could be analyzed under scanning electron microscopy (SEM). Internal root resorption was also classified as 0, 1, 2 or 3 according to the extent of the resorbed area. Additionally, six vital teeth were used as a control. Results, Non-cystic lesions with severe abscesses were the most common finding (70.7%), while 20% of the lesions were cystic (4% little or no abscess; 16% severe abscesses). Non-cystic lesions with little or no abscess comprised 9.3% of the sample. Of the root canals containing periapical lesions, 48% had internal apical resorption in more than half of the area, while 25.3% of the sample had no internal resorption. Resorption degree 1 was identified in 12% of the cases, and 14.7% showed resorption degree 2. The control group displayed significantly less internal resorption than the test groups. Conclusions, Most periapical lesions (86.7%), whether cystic (16.0%) or non-cystic (70.7%), showed large collections of acute inflammatory cells. Apical internal resorption was present in 74.7% of roots and was associated with periapical lesions. There was no correlation between internal apical resorption and the histological diagnosis of the lesions. [source] Apical inflammatory root resorption: a correlative radiographic and histological assessmentINTERNATIONAL ENDODONTIC JOURNAL, Issue 6 2000M. Laux Abstract Aim To assess the reliability of routine single radiographs in the diagnosis of inflammatory apical root resorption by correlating the radiographic and histological findings. Methodology The material comprised serial and step serial sections of plastic-embedded root-apices with attached apical periodontitis lesions that were prepared for a previous study and the diagnostic radiographs. The histological sections of 114 specimens were analysed by light microscopy and categorized into three groups: (i) those without any resorption (0); (ii) those with moderate resorption (+); and (iii) those with severe resorption (+ +). The radiographs were examined by a separate examiner and graded with a similar categorization of no resorption (0); moderate (+); and severe (+ +) apical resorption. Results Radiographically, 19% of the teeth were diagnosed as having apical inflammatory root resorption, whereas histologically, 81% of the teeth revealed apical inflammatory root resorption. A correlative radiographic and histological assessment (n = 104) revealed a coincidence of diagnosis in 7% of the specimens and noncoincidence of diagnosis in 76% of the specimens. Conclusions The results indicate that routine single radiographs are not sufficiently accurate or sensitive to consistently diagnose apical root resorptive defects developing as a consequence of apical periodontitis. [source] Pulpal status of human primary teeth with physiological root resorptionINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 1 2009JOANA MONTEIRO Objective., The overall aim of this study was to determine whether any changes occur in the pulpal structure of human primary teeth in association with physiological root resorption. Methods., The experimental material comprised 64 sound primary molars, obtained from children requiring routine dental extractions under general anaesthesia. Pulp sections were processed for indirect immunofluorescence using combinations of: (i) protein gene product 9.5 (a general neuronal marker); (ii) leucocyte common antigen CD45 (a general immune cell marker); and (iii) Ulex europaeus I lectin (a marker of vascular endothelium). Image analysis was then used to determine the percentage area of staining for each label within both the pulp horn and mid-coronal region. Following measurement of the greatest degree of root resorption in each sample, teeth were subdivided into three groups: those with physiological resorption involving less than one-third, one-third to two-thirds, and more than two-thirds of their root length. Results., Wide variation was evident between different tooth samples with some resorbed teeth showing marked changes in pulpal histology. Decreased innervation density, increased immune cell accumulation, and increased vascularity were evident in some teeth with advanced root resorption. Analysis of pooled data, however, did not reveal any significant differences in mean percentage area of staining for any of these variables according to the three root resorption subgroups (P > 0.05, analysis of variance on transformed data). Conclusions., This investigation has revealed some changes in pulpal status of human primary teeth with physiological root resorption. These were not, however, as profound as one may have anticipated. It is therefore speculated that teeth could retain the potential for sensation, healing, and repair until advanced stages of root resorption. [source] Idiopathic generalized apical root resorption: a report of three casesINTERNATIONAL JOURNAL OF PAEDIATRIC DENTISTRY, Issue 4 2008AILBHE McMULLIN Background. Idiopathic apical root resorption usually presents as a chance radiographic finding. It may be widespread, affecting the majority of teeth, with implications for the longevity of the dentition. Case report. Three cases of significant idiopathic apical resorption resulting, respectively, in prevention, abandonment, and alternative methods of orthodontic treatment are described. Conclusion. Significant idiopathic resorption may present as a chance radiographic finding, as pain, or excessive mobility. The prognosis for affected teeth is often poor with very limited scope for orthodontic movement due to the likelihood of uncontrolled resorption. Definitive prosthetic rehabilitation is often best deferred until adulthood due to the potential for further resorption during adolescence in addition to vertical growth considerations. [source] Effect of enamel matrix proteins (Emdogain®) on healing after re-implantation of "periodontally compromised" rootsJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 10 2003An experimental study in the dog Abstract Objective: The present experiment was performed to assess whether Emdogain® applied on the root surface of extracted teeth or teeth previously exposed to root planning can protect the tooth from ankylosis following re-implantation. Material and Methods: The experiment included two groups of dogs, including five animals each. The root canals of all mandibular third premolars (3 P 3) were reamed and filled with gutta-percha. A crestal incision was placed from the area of the second to the fourth premolar. Buccal and lingual full thickness flaps were elevated. With the use of a fissure bur, the crown and furcation area of 3 P 3 were severed in an apico-coronal cut. The distal and mesial tooth segments were luxated with an elevator and extracted with forceps. Group A: The mesial and distal segments of 3 P 3 were air dried on a glass surface for 60 min. The roots from the right side were conditioned and exposed to Emdogain® application. The roots from the left side received the same treatment with the exception of Emdogain® application. The mesial and distal tooth segments were re-implanted and the crown portions were severed with a horizontal cut and removed. The buccal and lingual flaps were mobilized and sutured to obtain complete coverage of the submerged roots. Group B: A notch was prepared in each root, 4,5 mm apical of the cemento-enamel junction. The area of the root that was located coronal to the notch was scaled and planned. The roots in the right side of the mandible were treated with Emdogain®, while the roots in the left side served as controls. After 6 months of healing, the dogs were killed and blocks containing one root with surrounding tissues were harvested, and prepared for histological examination, which also included morphometric assessments. Thus, the proportions of the roots that exhibited signs of (i) replacement (ii) inflammatory and (iii) surface resorption were calculated. Results and Conclusion: It was demonstrated that healing of a re-implanted root that had been extracted and deprived of vital cementoblasts was characterized by processes that included root resorption, ankylosis and new attachment formation. It was also demonstrated that Emdogain® treatment, i.e. conditioning with EDTA and placement of enamel matrix proteins on the detached root surface, failed to interfere with the healing process. Zusammenfassung Zielsetzung: Untersuchung, ob Emdogain®, wenn es auf die Wurzeloberfläche extrahierter Zähne oder von Zähnen, die zuvor eine Wurzelglättung bekommen haben, appliziert wird, die Zähne nach Reimplantation vor Ankylose schützen kann. Material und Methoden: Die Studie wurde bei 2 Gruppen von Hunden durchgeführt, die je 5 Tiere umfasste. Die Wurzelkanäle aller 3. Prämolaren des Unterkiefers (3 P 3) wurden aufbereitet und mit Guttapercha gefüllt. Ein Schnitt auf dem Limbus alveolaris wurde vom 2. zum 4 Prämolaren geführt. Bukkal und lingual wurde ein Vollschichtlappen mobilisiert. Mit einem Fissurenbohrer wurden die 3 P 3 mit einem Schnitt in koronoapikaler Richtung im Bereich der Krone und der Furkation geteilt. Die distalen und mesialen Zahnsegmente wurden mit einem Elevator luxiert und mit einer Zange extrahiert. Gruppe A: Die mesialen und distalen Segmente von 3 P 3 wurden auf einer Glasoberfläche 60 min lang luftgetrocknet. Die Wurzeln der rechten Seite wurden konditioniert und mit Emdogain® beschickt. Die Wurzeln der linken Seite erhielten die gleiche Behandlung mit der Ausnahme, dass keine Applikation von Emdogain® erfolgte. Die mesialen und distalen Wurzeln wurden reimplantiert und die Kronenanteile durch einen horizontalen Schnitt getrennt und entfernt. Die bukkalen und lingualen Lappen wurden mobilisiert und durch Naht ein vollständiger Verschluss der reimplantierten Wurzeln erreicht. Gruppe B: In jede Wurzel wurde 4,5 mm apikal der Schmelz-Zement-Grenze eine Kerbe präpariert. Der Bereich der Wurzel, der koronal dieser Kerbe lag, wurde gescalt und wurzelgeglättet. Die Wurzeln der rechten Unterkieferseite wurden mit Emdogain® behandelt, während die Wurzeln der linken Seite als Kontrolle dienten. Nach einer Heilung von 6 Monaten wurden die Hunde getötet und Blöcke, die eine Wurzel und das umgebende Gewebe enthielten, gewonnen und für die histologische Untersuchung präpariert, die auch morphometrische Befunde einschloss. Es wurden also die Anteile der Wurzeln berechnet, die Zeichen von (i) Ersatz- (ii) entzündlicher und (iii) Oberflächenresorption zeigten. Ergebnisse und Schlussfolgerungen: Es wurde gezeigt, dass die Heilung von reimplantierten Wurzeln, die extrahiert und von vitalen Zementoblasten befreit worden waren, durch Prozesse charakterisiert war, die Wurzelresorption, Ankylose und die Bildung neuen Attachments umfassten. Es wurde gezeigt, dass die Behandlung mit Emdogain®, d.h. Konditionierung mit EDTA und Applikation des Schmelz-Matrix-Proteins auf die freie Wurzeloberfläche diesen Heilungsprozess nicht beeinflussen konnte. Résumé Objectif: Cette expérimentation fut réalisée pour déterminer si Emdogain® appliqué sur la surface radiculaire de dents extraites ou de dents préalablement soumises à un surfaçage radiculaire pouvait protéger la dent de l'ankylose après réimplantation. Matériel et Méthodes: L'expérience comprenait 2 groupes de 5 chiens. Les canaux radiculaires de toutes les troisièmes premolaires mandibulaires (3 P 3) furent alésés et bouchés à la gutta-percha. Une incision crestale de la deuxième à la quatrième prémolaire permit de soulever un lambeau de pleine épaisseur vestibulaire et lingual. La couronne et la zone de furcation de 3 P 3 furent découpées à l'aide d'une fraise fissure d'apical en coronaire. Les segments distaux et mésiaux furent luxés avec un élévateur et extraits avec un davier. Groupe A: Les segments mésiaux et distaux de 3 P 3 furent séchés à l'air sur une plaque de verre pendant 60 min. Les racines du coté droit furent préparées et imprégnées d' Emdogain®. Les racines gauches reçurent le même traitement sans application d'Emdogain ®. Les segments mésiaux et distaux furent alors réimplantés et les couronnes découpées par un trait horizontal et éliminées. Les lambeaux vestibulaires et linguaux furent déplacés et suturés pour obtenir un recouvrement complet des racines enfouies. Groupe B: Une entaille a été préparée sur chaque racine, à 4,5 mm en apical de la jonction amélo-cémentaire. La surface de racine située coronairement à cette entaille fut alors détartrée et surfacée. Les racines du coté droit furent traitées par Emdogain® alors que les racines du coté gauche firent office de contrôle. Après 6 mois de cicatrisation, les chiens furent sacrifiés et des blocs contenant une racine et les tissus environnant furent prélevés pour un examen histologique et morphométrique. Ainsi, les proportions de racine présentant des signes de (i) remplacement (ii) d'inflammation et (iii) de résorption furent calculées. Résultats et conclusion: Nous avons démontré que la cicatrisation de racine réimplantées après extraction et élimination des cémentoblastes se caractérisait par un processus qui comprenait résorption radiculaire, ankylose et formation d'une nouvelle attache. Nous avons aussi démontré que le traitement par Emdogain®, c'est à dire conditionnement à l'EDTA et mise en place de protéines de la matrice améllaire sur la surface radiculaire, ne pouvait pas interférer avec le processus de cicatrisation. [source] Generalized cervical root resorption associated with periodontal diseaseJOURNAL OF CLINICAL PERIODONTOLOGY, Issue 11 2001Wouter Beertsen Abstract Background and description of case: The etiology and pathogenesis of generalized cervical root resorptions is not well understood. In the present report, a case of severe cervical root resorption involving 24 anterior and posterior teeth is presented. The lesions developed within a period of 2 years after the patient had changed to an acid-enriched diet. They extended far into the coronal dentin and were associated with gingival inflammation and crestal bone resorption. However, no generalized clinical attachment loss had occurred. Culturing of subgingival plaque revealed the presence of several putative periodontal pathogens among which Actinobacillus actinomycetemcomitans and Porphyromonas gingivalis. Treatment consisted of mechanical debridement supported by systemic antibiotics (amoxycillin plus metronidazole) and dietary advice. Results: Within 1 year after the onset of treatment, all resorptive lesions had repaired by ingrowth of a radio-opaque mineralized tissue. The crestal areas showed radiological evidence of bone repair. 3 years after the onset of therapy, one premolar was extracted and examined histologically. It appeared that irregularly-shaped masses of woven bone-like tissue had invaded into the domain of the resorbed coronal dentin and were bordered by thin layers of acellular cementum. Conclusion: It is concluded that, in this patient, the cervical resorptions were likely the result of an osteoclastic response extending into the roots because the root-protective role of the junctional epithelium did not develop. We hypothesize that this was due to the combined effects of a periodontopathogenic microflora and a dietary confounding factor. Zusammenfassung Hintergrund und Beschreibung des Falls: Die Ätiologie und die Pathogenese der generalisierten Wurzelresorptionen ist nicht besonders bekannt. In der vorliegenden Fallpräsentation wird ein schwerer Fall von Wurzelresorption gezeigt, die 24 anteriore und posteriore Zähne einbezog. Die Läsionen entwickelten sich innerhalb einer Periode von 2 Jahren, nachdem der Patient zu einer Säure-angereicherten Diät gewechselt hatte. Die Läsionen dehnten sich in das koronale Dentin aus und waren mit gingivaler Entzündung und krestaler Knochenresorption verbunden. Jedoch wurde kein generalisierter Attachmentverlust beobachtet. Die Kultur der subgingivalen Plaque erbrachte das Vorhandensein von verschiedenen putativen parodontalen Pathogenen, unter ihnen Actinobacillus actinomycetemcomitans und Porphyromonas gingivalis. Die Behandlung bestand in der mechanischen Reinigung unterstützt mit systemischen Antibiotika (Amoxicillin und Metronidazol) und Diätanweisungen. Ergebnisse: Innerhalb eines Jahres nach dem Beginn der Therapie waren alle Resorptionsläsionen repariert durch das Einwachsen von röntgenopakem mineralisierten Gewebe. Die krestalen Regionen zeigten radiologisch nachgewiesene Knochenreparatur. 3 Jahre nach Therapiebeginn wurde ein Prämolar extrahiert und histologisch untersucht. Es schien, daß irreguläre geformte Massen von verflochtenem knochen-ähnlichen Gewebe in den Hauptteil des resorbierten koronalen Dentins hineingelangt sind und von dünnen Schichten azellulären Zementes begrenzt wurden. Zusammenfassung: Es wird geschlußfolgert, daß bei diesem Patient die zervikalen Resorptionen wahrscheinlich das Ergebnis einer osteoklastischen Reaktion waren, bis in die Wurzeln ausgedehnt, weil sich die wurzelschützende Rolle des Verbindungsepithels nich entwickelt hatte. Wir nehmen an, daß dies in der Folge eines kombinierten Effektes von parodontopathogenen Keimen und eines verwirrenden diätetischen Faktors geschah. Résumé Origine: L'étiologie et la pathogenèse des résorptions radiculaires cervicales généralisées ne sont pas suffisamment connues. Dans le rapport présent, un cas de résorption radiculaire cervicale sévère se rapportant à 24 dents antérieures et postérieures est présenté. Les lésions s'étaint développées durant les 2 années qui ont suivi le changement de régime alimentaire du patient vers un régime plus acide. Elles s'étendaient profondément dans la dentine coronaire et étaient associées à une inflammation gingivale et une résorption osseuse crestale. Cependant, aucune perte d'attache clinique généralisée n'est apparue. La culture de la plaque dentaire sous-gingivale a révélé la présence de plusieurs pathogènes parodontaux putatifs parmi lesquels l'Actinobaccilus actinomycetemcomitans et le Porphyromonas gingivalis. Le traitement a consisté en un nettoyage mécanique associéà l'utilisation d'antibiotiques par voie systémique (amoxycilline + métronidazole) et un conseil diététique. Résultats. Dans l'année qui a suivi ce traitement, toutes les lésions de résorption ont été guéries par la croissance d'un tissu minéralisé radio-opaque. Les zones crestales montraient une évidence radiologique de réparation osseuse. 3 ans après le démarrage de ce traitement, une prémolaire a été avulsée et examinée histologiquement. Il est apparu que des masses de formes irrégulières de tissus ressemblant à de l'os ouaté avaient envahi le domaine de dentine coronaire résorbé et étaient entourées par de fines couches de cément acellulaire. Conclusions: Chez ce patient, les résorptions cervicales étaient vraisemblablement dûes à une réponse ostéoclastique s'étendant dans les racines parce que le rôle de protection radiculaire de l'épithélium de jonction ne s'étaient pas développé. Cette situation était vraisemblablement dûe à des effets combinés de la microflore parodonto-pathogène et d'un facteur diététique. [source] Dental root resorption and repair: histology and histometry during physiological drift of rat molarsJOURNAL OF PERIODONTAL RESEARCH, Issue 5 2003Ryusei Kimura Objective:, The process of dental root resorption and subsequent cementum regeneration has not been sufficiently elucidated. This study aimed to examine the process of the root resorption and cementum regeneration during physiological tooth drift using a rat model, and to evaluate this experimental model. Methods:, Distal roots in mandibular first molars and the surrounding periodontal tissues were investigated with light and electron microscopy. The light microscopic approach included histochemical and histometric analyses utilizing the tartrate-resistant acid phosphatase (TRAP) reaction. Results:, Root resorption was observed in the distal side of the roots and was most active in 5- to 6-week-old rats, and gradually decreased hereafter. An increase in the number of TRAP-positive mononuclear cells, which seemed to be odontoclast precursor cells, preceded the increase in the number of odontoclasts. Root resorption was transient, and was followed by the new formation of acellular extrinsic fiber cementum accompanied with only a slight inflammation, and therefore classified as external surface resorption. Preparation for new cementum started adjacent to the resorption areas when root resorption was most active. Conclusions:, The root resorption during drift in rats is transient and followed by acellular extrinsic fiber cementum regeneration. Cellular kinetics suggested that odontoclast precursor cells are supplied as mononuclear cells from vascular spaces. [source] Recombinant human basic fibroblast growth factor (bFGF) stimulates periodontal regeneration in class II furcation defects created in beagle dogsJOURNAL OF PERIODONTAL RESEARCH, Issue 1 2003S. Murakami Several growth factors (or cytokines) have been recently investigated for their use as potential therapeutics for periodontal tissue regeneration. The objective of this study was to evaluate periodontal tissue regeneration, including new bone and cementum formation, following topical application of recombinant basic fibroblast growth factor (bFGF, FGF-2) to furcation class II defects. Twelve furcation class II bone defects were surgically created in six beagle dogs, then recombinant bFGF (30 µg/site) + gelatinous carrier was topically applied to the bony defects. Six weeks after application, periodontal regeneration was analyzed. In all sites where bFGF was applied, periodontal ligament formation with new cementum deposits and new bone formation was observed histomorphometrically, in amounts greater than in the control sites. Basic FGF-applied sites exhibited significant regeneration as represented by the new bone formation rate (NBR) (83.6 ± 14.3%), new trabecular bone formation rate (NTBR) (44.1 ± 9.5%), and new cementum formation rate (NCR) (97.0 ± 7.5%). In contrast, in the carrier-only sites, the NBR, NTBR, and NCR were 35.4 ± 8.9%, 16.6 ± 6.2%, and 37.2 ± 15.1%, respectively. Moreover, no instances of epithelial down growth, ankylosis, or root resorption were observed in the bFGF-applied sites examined. The present results indicate that topical application of bFGF can enhance considerable periodontal regeneration in artificially created furcation class II bone defects of beagle dogs. [source] Feline odontoclastic resorptive lesions: unveiling the early lesionJOURNAL OF SMALL ANIMAL PRACTICE, Issue 11 2002C. Gorrel The purpose of this study was to increase understanding of the factors initiating feline odontoclastic resorptive lesions (FORLs). Fifty-six teeth (clinically and radiographically unaffected by ORLs) were harvested. Of these, 43 were from cats that had ORLs in other teeth (group A) and 13 were from cats with no clinical or radiographic evidence of ORLs in any teeth (group B). Twenty-six teeth in group A and one tooth in group B showed histological evidence of external root resorption (surface resorption and replacement resorption resulting in ankylosis). Some teeth in group B showed healed cementum resorption. It has previously been assumed that FORLs were similar to lesions associated with peripheral inflammatory root resorption, and were associated with periodontal disease. These histological findings suggest instead that a FORL is a non-inflammatory replacement resorption, resulting in ankylosis. The periodontal ligament of resorbing teeth lacked normal fibrous architecture, but was not inflamed. Resorption was not identified in cervical cementum. However, the histological appearance of the cervical cementum differed between the two groups. Several aetiopathogenetic explanatory models which arise from these observations are discussed. [source] Differentiation and functions of osteoclasts and odontoclasts in mineralized tissue resorptionMICROSCOPY RESEARCH AND TECHNIQUE, Issue 6 2003Takahisa Sasaki Abstract The differentiation and functions of osteoclasts (OC) are regulated by osteoblast-derived factors such as receptor activator of NFKB ligand (RANKL) that stimulates OC formation, and a novel secreted member of the TNF receptor superfamily, osteoprotegerin (OPG), that negatively regulates osteoclastogenesis. In examination of the preosteoclast (pOC) culture, pOCs formed without any additives expressed tartrate-resistant acid phosphatase (TRAP), but showed little resorptive activity. pOC treated with RANKL became TRAP-positive OC, which expressed intense vacuolar-type H+ -ATPase and exhibited prominent resorptive activity. Such effects of RANKL on pOC were completely inhibited by addition of OPG. OPG inhibited ruffled border formation in mature OC and reduced their resorptive activity, and also induced apoptosis of some OC. Although OPG administration significantly reduced trabecular bone loss in the femurs of ovariectomized (OVX) mice, the number of TRAP-positive OC in OPG-administered OVX mice was not significantly decreased. Rather, OPG administration caused the disappearance of ruffled borders and decreased H+ -ATPase expression in most OC. OPG deficiency causes severe osteoporosis. We also examined RANKL localization and OC induction in periodontal ligament (PDL) during experimental movement of incisors in OPG-deficient mice. Compared to wild-type OPG (+/+) littermates, after force application, TRAP-positive OC were markedly increased in the PDL and alveolar bone was severely destroyed in OPG-deficient mice. In both wild-type and OPG-deficient mice, RANKL expression in osteoblasts and fibroblasts became stronger by force application. These in vitro and in vivo studies suggest that RANKL and OPG are important regulators of not only the terminal differentiation of OC but also their resorptive function. To determine resorptive functions of OC, we further examined the effects of specific inhibitors of H+ -ATPase, bafilomycin A1, and lysosomal cysteine proteinases (cathepsins), E-64, on the ultrastructure, expression of these enzymes and resorptive functions of cultured OC. In bafilomycin A1-treated cultures, OC lacked ruffled borders, and H+ -ATPase expression and resorptive activity were significantly diminished. E-64 treatment did not affect the ultrastructure and the expression of enzyme molecules in OC, but significantly reduced resorption lacuna formation, by inhibition of cathepsin activity. Lastly, we examined the expression of H+ -ATPase, cathepsin K, and matrix metalloproteinase-9 in odontoclasts (OdC) during physiological root resorption in human deciduous teeth, and found that there were no differences in the expression of these molecules between OC and OdC. RANKL was also detected in stromal cells located on resorbing dentine surfaces. This suggests that there is a common mechanism in cellular resorption of mineralized tissues such as bone and teeth. Microsc. Res. Tech. 61:483,495, 2003. © 2003 Wiley-Liss, Inc. [source] | |||||||||||||||||||