• The korean journal of orthodontics
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• v.41 no.3
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• pp.174-183
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• 2011

Objective: Orthodontically induced root resorption (OIRR) involves partial loss of cementum and dentin of teeth caused by routine orthodontic treatment. It decreases root length and influences the function of affected teeth. In this study, the treatment and patient factors causing apical root resorption in Koreans were determined. The observed factors were extraction, gender, age, displacement of root apex, total treatment period, total teeth length, and shape of the root. Methods: The records of 137 patients treated with full, fixed edgewise appliances were obtained from the Department of Orthodontics, Dankook University Dental Hospital, from November 2007 to December 2008. Periapical radiographs of the maxillary central incisors and cephalometric radiographs of each patient were used to assess apical root resorption and type of tooth movement. Results: The mean amount of resorption was $1.62{\pm}1.58mm$. The amount of resorption in the extraction and non-extraction groups was $2.10{\pm}1.64mm$ and $1.18{\pm}1.39mm$, respectively. The amount of root resorption increased with the total tooth length. Severe root resorption (> 4 mm) was related to abnormal root shape (blunt, pointed, or eroded). Conclusions: The variables significantly related to OIRR were extraction, initial tooth length, and root shape.

• The korean journal of orthodontics
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• v.34 no.6 s.107
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• pp.526-536
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• 2004

This study was undertaken to determine the effect of a 2.2mg/Kg/day intraoral administration of NaF on the amount of root resorption and osteoclastic activity during or after a rapid maxillary expansion procedure. Ten puerile female dogs were divided into two groups: a control group and a NaF-treated group. A fixed type maxillary expansion device was delivered to all dogs. The appliance was activated twice daily throughout a 20-day period, causing a 5-mm expansion of maxillary bone. After the expansion procedure, the animals were sacrificed at days 0, 15, 30, 45, and 60 of the retention period. The buccal surface of the root of each maxillary canine was examined by means of a surface electron microscope (SEM). Using SEM, web-like resorption lacunae were observed on the bone or the tooth surface at the site of osteoclastic activity; these observations were verified by histological methods. No peculiar resorption lacunae were found in the apical tip of the roots of either the control group or the NaF-treated group animals. The NaF-treated retention group was found to have less resorption lacunae formation on day 45 and day 60. The preventative effect of NaF on resorption lacunae formation on the surface of the bone covering the anchor tooth was confirmed. Larger areas of resorption lacunae were found on the surface of the bone covering the canines in the control group animals, as compared to those of the NaF-treated group, especially on day 30 and day 60. Using SEM, the present study revealed a difference between the control group and the NaF-treated group in the prevalence and the size of the resorption lacunae formation on the cemental root surface. The preventative effect of NaF on bone resorption was confirmed. Further studies concerned with the optimum concentration of NaF that has an effect in vivo are necessary.

• The korean journal of orthodontics
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• v.47 no.6
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• pp.365-374
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• 2017

Objective: The objective of this study is to investigate the eruption pattern and root resorption of the bovine anterior dentition in relation to growth-related parameters based on dental maturity. Methods: A cross-sectional study was conducted on 110 bovine anterior mandibles by using standard radiography, cone-beam computed tomography (CBCT), and actual measurements. We determined the relationships between the stages of dental maturity by using a modification of Demirjian's method and various growth-related parameters, such as the activity of the root-resorbing tissue and mobility of the deciduous teeth. The correlation of growth-related parameters with interdental spacing and distal unusual root resorption (DRR) of the deciduous fourth incisor was assessed. The cause of mesial unusual root resorption (MRR) of the deciduous fourth incisor was determined on the basis of the arrangement of the permanent third incisor. Results: An independent t-test and chi-square test indicated significant differences in growth-related parameters associated with dental arch length discrepancy and factors related to the shedding of deciduous teeth between the low and high dental maturity groups. The samples with interdental spacing and DRR showed a larger sum of mesiodistal permanent crown widths and higher dental maturity than did the respective controls. Samples with MRR tended to show a lingually rotated distal tip of the adjacent tooth crown. Conclusions: Dental maturity has relevance to the interdental spaces and unusual root resorption of mixed dentition. The position of the adjacent tooth crown on CBCT may be correlated with the occurrence of unusual root resorption of the incisor.

• Journal of Korean Dental Science
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• v.1 no.1
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• pp.4-9
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• 2008

Purpose : This study sought to examine the aspects of crestal bone resorption and to evaluate the clinical outcomes of the TiUnite$^{(R)}$ (Nobel Biocare, Sweden) anodized implant system. Materials and Methods : Among the 67 patients (211 fixtures) who were treated using TiUnite(r) implants at Seoul National University Bundang Hospital between March 2004 and January 2007, 26 (91 fixtures) were considered in this study. Initial and secondary stabilities were measured using Periotest$^{(R)}$ and Ostell(tm) Mentor. The radiographic evaluation of crestal bone resorption was carried out by measuring the change in crestal bone level at the time of surgery compared to that 1 year after loading. Panoramic radiograph and periapical radiograph were used. Based on the radiographic findings, the shapes of crestal bone resorption were classified. Results : The average amount of crestal bone resorption after 1 year of functional implant loading was 0.30 mm. There was no saucerization in 40 implant fixtures (43.9%), although more than 1 thread were exposed in 51 implant fixtures (56.6%). The success rate of the implants was 94.5%, and the survival rate was 100%. Conclusions : Good clinical outcomes and minor crestal bone resorption were noted in this study. Saucerization for the establishment of biological width was not a general finding in the TiUnite$^{(R)}$ anodized implant system.

• Archives of Plastic Surgery
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• v.32 no.4
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• pp.511-515
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• 2005

Autologous cartilage grafts have become an integral part of aesthetic and reconstructive plastic surgery. However, little objective information is available about the actual quantitative resorption of cartilage in human. This study sought to objectively quantify and compare the resorption of costal cartilage in human. To compare the resorption characteristics of rib cartilage autografts, we harvested rib cartilage grafts from 37 microtia patients. All autografts were implanted subcutaneously on chest and then removed after 6 to 17 months. Graft mass and volume were compared before and after implantion. Rib cartilage grafts with perichondrium averaged $10.8{\pm}7.4%$ resorption by volume, On the other hand rib cartilage grafts without perichondrium $25.5{\pm}6.8%$. There was no evidence of necrosis or inflammatory changes. The rib cartilage is the preferred source of autogenous cartilage for auricular reconstruction. Short-term resorption of rib cartilage without perichondrium appears to be higher than with perichondrium. The low resorption of cartilage with perichondrium may be due to in part to cartilage forming capacity of the perichondrium. It remains to be seen whether these differences in resorption persist in the long term.

• The korean journal of orthodontics
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• v.21 no.1 s.33
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• pp.77-96
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• 1991

Many studies has been conducted concerning prevention of unnecessary complications such as root resorption during orthodontic too th movement under various mechanical forces. Nowadays, the cause of the root resorption is not thought to be confined only to mechanical forces. But the factor that affects bone metabolism are thought to be major one of the predisposing factors. The light microscope and scanning electron microscope were used to the effects of 60 gm, and 100 gm of tipping force on root resorption of cats, which were treated with Etidronate disodium. The results were as follows: 1. In the 60gm control group, hyalinization on the compression site of periodontal ligament appeared after first week and second week. In the 60gm experimental group, it appeared after first week with low frequency. In the 100gm control group it appeared with high frequency by first and second week while in 100gm experimental group, it appeared with low frequency. 2 In the 100gm control group, resorption of the cementum and the alveolar bone rapidly increased after second week. In the 60gm experimental group, resorption or formation of alveolar bone and cementum didn't appear all through the experimental period. 3. In the 100gm control group, formation of cementum and alveolar bone appeared after first week while in the 100gm experimental group, formation of cementum and alveolar bone appeared after second week and fourth week respectively. In the 60gm control group, formation of the cementum didn't appear all through the experimental period. 4. In the control group, the root resolution of 100gm group was higher than that of 60gm group after second week, while in experimental group, root resorption didn't appear regardless of the forces.

• Imaging Science in Dentistry
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• v.46 no.1
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• pp.17-24
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• 2016

Purposes: This study employed a posteriori registration and subtraction of radiographic images to quantify the apical root resorption in maxillary permanent central incisors after orthodontic treatment, and assessed whether the external apical root resorption (EARR) was related to a range of parameters involved in the treatment. Materials and Methods: A sample of 79 patients (mean age, $13.5{\pm}2.2years$) with no history of trauma or endodontic treatment of the maxillary permanent central incisors was selected. Periapical radiographs taken before and after orthodontic treatment were digitized and imported to the Regeemy software. Based on an analysis of the post-treatment radiographs, the length of the incisors was measured using Image J software. The mean EARR was described in pixels and relative root resorption (%). The patient's age and gender, tooth extraction, use of elastics, and treatment duration were evaluated to identify possible correlations with EARR. Results: The mean EARR observed was $15.44{\pm}12.1pixels$ (5.1% resorption). No differences in the mean EARR were observed according to patient characteristics (gender, age) or treatment parameters (use of elastics, treatment duration). The only parameter that influenced the mean EARR of a patient was the need for tooth extraction. Conclusion: A posteriori registration and subtraction of periapical radiographs was a suitable method to quantify EARR after orthodontic treatment, and the need for tooth extraction increased the extent of root resorption after orthodontic treatment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.49 no.5
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• pp.278-286
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• 2023

Objectives: This review assessed the performance of implant-supported fixed hybrid prostheses in 21 patients who received a total of 137 implants between 2003 and 2010. The implants were evaluated for marginal bone resorption, complications, success rate, and survival rate based on their vertical angularity, type of bone graft, and measured implant stability. Materials and Methods: One-way ANOVA and chi-square tests were used to analyze the relationships among long-term evaluation factors and these variables. The mean initial bone resorption in the implant group with a vertical angle of more than 20° was 0.33 mm and mean final bone resorption was 0.76 mm. In contrast, the mean initial bone resorption in the implant group with a vertical angle of less than 10° was 1.19 mm and mean final bone resorption was 2.17 mm. Results: The results showed that mean bone resorption decreased with an increase in the vertical placement angle of the implants used in fixed hybrid prostheses, as well as in the group without additional bone grafts and those with high implant stability. The success rate of implants placed after bone grafting was found to be higher than those placed simultaneously. Conclusion: These results suggest that implant-supported fixed hybrid prostheses may be an effective treatment option for edentulous patients, and intentionally placing implants with high angularity may improve outcomes.

• Journal of Oral Medicine and Pain
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• v.31 no.4
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• pp.337-346
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• 2006

Aims: The present study investigated the relationship between condylar resorption and craniofacial skeleton types(especially vertical relationships), the differences of craniofacial skeleton types between with open bite group and without open bite group, and the associations of anterior disc dislocation with or without reduction to condylar resorption with MRI. Patients selection and methods: Clinical examination, magnetic resonance imaging (MRI), panorama, lateral transcranial and lateral cephalometric radiographs in 34 patients with condylar resorption were used to investigate this relationship. Results and Conclusions: Patients with the following specific facial morphologic characteristics appear to be most susceptible to condylar resorption: (1) females were predominant, (2) patients' age ranged from 12 to 50 years old with a strong predominance for 2nd and 3rd decades, (3) patients had high mandibular plane angle and high gonial angle, (4) patients had decreased vertical height of the ramus, (5) patients had generally significant antegonial notch, (6) patients had predominance of Class I occlusal relationship with or without open bite but mandible was retruded as mean ANB 5.54 degrees, (7) condylar resorption rarely occurs in lower mandibular plane angle facial types, (8) although no statistically significant difference was found, the open bite group had a tendency more hyperdivergent skeletal pattern than the non open bite group, and (9) imaging demonstrates from small resorbing condyles to idiopathic condylar resorption and TMJ articular disc dislocations. Thus, morphologic features of patients with vertical discrepancies may represent a risk factor for the development of condylar resorption.

• The Journal of Korean Academy of Prosthodontics
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• v.59 no.4
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• pp.405-414
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• 2021

Purpose. This study was conducted to evaluate clinical usefulness by evaluating the marginal bone resorption and survival rate of an implant with a taper straight type SLA surface domestically available on the market recently. Materials and methods. 40 implants satisfying the including criteria were observed for one year of 125 implants of 83 adult men and women who had KISPLANT^® implanted from August 2016 to December 2019 at the Department of Periodontology, Chonnam National University Dental Hospital. The marginal bone level was measured on periapical radiographs taken initially and 1 year later and we analyzed implant survival and success rates. A t-test was used for the analysis of the association between the marginal bone resorption and the severity of periodontitis, supportive periodontal therapy, the inserted site, the cause of extraction, immediate placement, and systemic disease. Results. After 1 year of loading, the mesial bone resorption was 0.74 ± 1.07 mm, and the distal bone resorption was 0.53 ± 1.04 mm. The marginal bone resorption of 2 mm or more occurred at 3 implants out of 40 implants after 1 year, so the success rate of implant was 92.5% and survival rate was 100%. There was a significant difference in mesial marginal bone resorption according to the inserted site and no significant differences were found between marginal bone resorption and the other factors. Conclusion. As a result of marginal bone resorption, success rate, and survival rate in this study, we found little marginal bone resorption and high survival and success rate. It can be concluded that they represent excellent clinical results.