• The korean journal of orthodontics
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• v.48 no.5
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• pp.339-345
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• 2018

Objective: The purpose of this study was to clarify the effects of continuous force application for extrusive tipping movement and occlusal interference on periapical root resorption in the rat mandibular first molar. Methods: We constructed an appliance comprising a titanium screw implant with a cobalt-chromium post as the anchorage unit and a nickel-titanium closed coil spring (50 cN) as the active unit. Force was applied on the mandibular left first molar of rats for 8 (n = 10) and 15 days (n = 10; experimental groups), with the tooth in occlusion. Five rats were included as a non-treated control group to examine the body effect of the appliance. Active root resorption lacunae, identified using tartrate-resistant acid phosphatase, were evaluated in terms of the length, depth, and area. Results: The rat mandibular first molars were mesially tipped and extruded in the occlusal direction. This mesio-occlusal tipping movement and occlusion resulted in the formation of a compression zone and active root resorption lacunae in the distoapical third of the distal roots. However, there was no significant difference in the amount of root resorption between the two experimental groups. The control group did not exhibit any active root resorption lacunae. Conclusions: Periapical root resorption was induced by continuous extrusive tipping force and occlusal interference in rat mandibular molars. These data suggest that we orthodontists had better take care not to induce occlusal interference during our orthodontic treatment.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.37 no.6
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• pp.483-489
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• 2011

Introduction: This study examined the cumulative resorption of implants placed in a severely atrophic mandible and analyzed the radiologic bone resorption in the marginal bone, after an autogenous bone graft including both block and particulates that had been harvested from the ramus and iliac crest. Materials and Methods: A retrospective study was performed on patients who had bone grafts for augmentation followed by implant installation in the mandible area from 2003 to 2008. Twelve patients (6 men and 6 women) who received 34 implants in the augmented sites were evaluated. Cumulative radiologic resorption around the implants was measured immediately, 3 months, 6 months and 12 months after implant installation surgery. Results: The installed implant in grafted bone showed 0.84 mm marginal bone resorption after 3 months and 50% total cumulative resorption after 1 year. The mean marginal bone resorption around the implant installed in the grafted bone was 0.44 mm after 3 months, 0.52 mm after 1 year, after which it stabilized. The implant survival rate was 97% (failed implant was 1/34). Marginal bone resorption of the installed implant in the autogenous onlay block bone grafts was 0.98 mm after 3 months, which was significantly higher than that of a particulated bone graft (0.74 mm) (P <0.05). Conclusion: An autogenous graft including block type and particulate type is a predictable procedure for the use of dental implants in a severely atrophic mandible. Implant placement in augmented areas show a relatively high survival and minimal bone loss, as revealed by a radiologic evaluation.

• Imaging Science in Dentistry
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• v.31 no.1
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• pp.51-55
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• 2001

Purpose : This study was performed to compare the diagnostic ability of conventional intraoral radiographs with that of digital subtraction image and to assess the quantifying ability of digital subtraction image for simulated apical root resorption Materials and Methods : Conventional intraoral radiographs and digital images of ten sound maxillary central incisors and those with simulated apical root resorption were taken with varying horizontal and vertical angulations of the x-ray beam. The diagnostic accuracy to detect the lesion was evaluated on conventional intraoral radiographs and digital subtraction images by ROC analysis. The amount of simulated apical root resorption was also estimated on the reconstruction images by Emago/sup (R)/ and compared with actual amount of tooth loss using paired t-test. Results: The diagnostic accuracy of conventional intraoral radiographs to detect the apical root resorption was low (ROC area = 0.6446), and the sensitivity and the specificity of digital subtraction images were 100%, respectively. The calculated amounts of apical root resorption showed no statistically significant difference with the actual amounts of the lesion (p>0.05). Conclusion: Digital subtraction radiography is powerful tool to detect the small apical root resorption, and quantitative analysis of small amounts of the lesion can be evaluated by digital subtraction radiography.

• The korean journal of orthodontics
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• v.50 no.3
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• pp.216-226
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• 2020

Root resorption can be caused by several factors, including contact with the cortical bone. Here we report a case involving a 21-year-old female with Angle Class II, division 1 malocclusion who exhibited significant root resorption in the maxillary right central incisor after orthodontic treatment. The patient presented with significant left-sided deviation of the maxillary incisors due to lingual dislocation of the left lateral incisor and a Class II molar relationship. Cephalometric analysis demonstrated a Class I skeletal relationship (A point-nasion-B point, 2.5°) and proclined maxillary anterior teeth (upper incisor to sella-nasion plane angle, 113.4°). The primary treatment objectives were the achievement of stable occlusion with midline agreement between the maxillary and mandibular dentitions and appropriate maxillary anterior tooth axes and molar relationship. A panoramic radiograph obtained after active treatment showed significant root resorption in the maxillary right central incisor; therefore, we performed cone-beam computed tomography, which confirmed root resorption along the cortical bone around the incisive canal. The findings from this case, where different degrees of root resorption were observed despite comparable degrees of orthodontic movement in the bilateral maxillary central incisors, suggest that the incisive canal could be an inducing factor for root resorption. However, further investigation is necessary to confirm this assumption.

• International Journal of Oral Biology
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• v.40 no.3
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• pp.111-116
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• 2015

To determine the effect of diabetes on root resorption in periodontitis, we investigated odontoclast formation and root resorption in diabetic rats with periodontitis. Odontoclast formation was observed in three groups of F344 rats: Controls (C) were normal rats without diabetes or periodontitis; the periodontitis (P) group had mandibular first molars to be ligatured; the periodontitis with diabetes (PD) group was intravenously administered streptozotocin (50 mg/kg) to induce diabetes and had mandibular first molars to be ligatured. On days 3, 10, and 20 after ligature, tumor necrosis factor (TNF)-${\alpha}$ and receptor activator of nuclear factor-${\kappa}B$ ligand (RANKL) expression, odontoclast formation, and root resorption areas were evaluated by immunohistochemistry, tartrate-resistant acid phosphatase staining, and hematoxylin and eosin staining, respectively. The PD group showed frequent urination, weight loss, and hyperglycemia. Numbers of TNF-${\alpha}$- and RANKL-positive cells were higher in the P and PD groups than in the C group. It was more prevalent in PD group on day 3. Odontoclast formation was greater in the P and PD groups than in the C group on days 3 and 10, then decreased to same level as the C group by day 20. Root resorption in the PD and P groups showed increases on days 3 and 10, respectively, compared to the C group. These results suggest that diabetes may transiently increase root resorption on day 3 with high expression of TNF-${\alpha}$ and RANKL after periodontitis induction. This study could aid the understanding of root resorption in diabetic patients with periodontitis.

• Proceedings of the Korean Society of Precision Engineering Conference
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• 2010.05a
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• pp.1385-1386
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• 2010

• Journal of Korean Dental Science
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• v.9 no.2
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• pp.63-68
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• 2016

Pressure root resorption can be observed during the eruption of permanent dentition, especially of the maxillary canines (affecting lateral incisors) and mandibular third molars (affecting mandibular second molars). Since the cause of root resorption of the adjacent affected teeth is evident, treatment simply involves extraction of the impacted tooth. However, there have been few reports on the prognosis of the remaining resorbed tooth, as dentists often choose to extract them when damage due to root resorption is observed. We report a case involving a tooth that was severely resorbed due to pressure from an adjacent impacted tooth. After extraction of the impacted tooth, the remaining tooth retained vital pulp and survived as a functional tooth.

• Proceedings of the KACD Conference
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• 2001.05a
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• pp.241-242
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• 2001

Tooth resorption os perplexing problem for all dental practitioners. The etiology factors and diagnosis are vague, chosen treatment dose not prevent the rapid disappearance of the calcified dental tissues. Since the etiologic factors, diagnosis, treatment and prognosis differ for these various types of resorptive defects, it is important to diagnose resorption radiographically or clinicall and distinguish internal from external resorption. Following these cases are internal root resorption, external root resorption of serious complication subsequent to avulsion and traumatic injury.

• Journal of Biomedical Engineering Research
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• v.16 no.1
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• pp.25-32
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• 1995

Clinically, proximal bone resorption in the femur is frequently seen postoperatively on the follow up XI-rays after total hip replacement (THR). We developed the finite element model of cementless THR. The model is two dimensional side plate model, whereby the three dimensional structural integrity of the bone can be accounted for by a separate two dimensional mesh, a side plate. The subject of this article is the development and application of this two dimensional side plate FEM to study the reverse effect of the various degree of bone resorption of femur after THR. The results of this study indicates that 1) two dimensional side plate model is good and simple alternative to complex three dimensional model and 2) the severity of the proximal bone resorption has the effect of more increasing stress on the cortex at the level of femoral stem tip.

• Journal of dental hygiene science
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• v.11 no.3
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• pp.251-255
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• 2011

Objectives One aspect of undesirable outcomes in orthodontic treatment includes excessive resorption of dental roots with mechanotherapy. The purpose of this study was to examine the relationship between treatment duration, adult and adolescent, gender, extraction and non-extraction root resorption after orthodontic treatment. Methods The subjects consisted of 140 orthodontic patients(adult : 70, adolescent : 70) who treated by standard edgewise technique at the three orthodontic hospital and clinic in seoul. Pre-treatment and post-treatment periapical radiographs were examined. The amount of root resorption was assessed for six anterior teeth according to criteria modified from Lupi et al root resorption score. Results Treatment duration was 24.7 months in the adult group and 33.5 months in the adolescents group. Between adult and adolescents group were significantly difference of mean of root resorption score(p<0.05). Female group and extraction group usually had higher prevalence of root resorption, but were not significant differences between the each groups(p>0.05). Conclusions When viewing these results, a lot of root resorption in adult patients appears, especially the maxillary central incisor, lateral incisor root resorption during orthodontic treatment occurs, so be careful and do more research to be done is suggested.