• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• v.36 no.5
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• pp.417-422
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• 2010

Introduction: Bone density is one of the important factors for the long term success of endosseous implants. The bone density varies from site to site and from patient to patient. A preoperative evaluation of the bone density is quite useful to oral surgeons for planning dental implantation. More accurate information on the bone density will help surgeons identify suitable implant sites, thereby increase the success rate of dental implantation. This study examined the correlation between the bone density measured preoperatively by computed tomography (CT) and the implant primary stability measured by resonance frequency analysis. Furthermore, the effects of the implant sites, gender, age and generalized systemic disorder patients on the bone density and primary implant stability were examined. Materials and Methods: One hundred and fourteen patients were selected. None of the patients had undergone a tooth extraction or bone graft history in the previous year. Preoperatively, the patients underwent CT scanning to evaluate the Hounsfield unit (HU), and resonance frequency analysis (RFA) was used to evaluate the implant primary stability at the time of implant installation. All implants were 4.0 mm diameter and 11.5 mm length US II. All patients were recorded and the HU and implant stability quotient (ISQ) value were evaluated according to the sites, gender and age. Results: The highest HU values were found in the mandibular anterior site ($827.6{\pm}151.4$), followed by the mandibular molar site ($797{\pm}135.1$), mandibular premolar site ($753.8{\pm}171.2$), maxillary anterior site ($726.3{\pm}154.4$), maxillary premolar site ($656.7{\pm}173.8$) and maxillary molar site ($621.5{\pm}164.9$). The ISQ value was the highest in the mandibular premolar site ($81.5{\pm}2.4$) followed by the mandibular molar site ($80.0{\pm}5.7$), maxillary anterior site ($77.4{\pm}4.1$), mandibular anterior site ($76.4{\pm}11.9$), maxillary premolar site ($74.2{\pm}14.3$) and maxillary molar site ($73.7{\pm}7.4$). The mean HU and ISQ value were similar in females and males. (HU: P=0.331, ISQ: P=0.595) No significant difference was also found in the age group respectively. However, the correlation coefficients between the variables showed a closed correlation between the HU and ISQ value. Conclusion: These results showed close correlation between the bone density (HU) and primary stability value (ISQ) at the time of implant installation (Correlation coefficients=0.497, P<0.01). These results strengthen the hypothesis that it might be possible to predict and quantify the initial implant stability and bone density from a presurgical CT diagnosis.

• Journal of Veterinary Clinics
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• v.34 no.6
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• pp.463-466
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• 2017

A 3-year-old, 26 kg, castrated male Chow Chow was presented for assessment of weight-bearing lameness of the left hind limb. The patient had a history of triple pelvic osteotomy on the left side to correct hip dysplasia 2 years prior to his presentation of clinical signs and underwent total hip replacement on the right coxofemoral joint 1 year later. Upon physical examination, pain and crepitus were noted on the left hip joint during extension. Radiological examination revealed coxofemoral joint subluxation and moderate degenerative bone changes on the left hip joint and pelvic axis, which relates to acetabular angles that were changed after triple pelvic osteotomy (TPO). Preoperative computed tomography was used for 3-dimensional printing to establish an accurate surgical plan. The changed angles of the acetabulum after TPO were evaluated, and rehearsal surgery was performed using a 3-demensional printing bone model. Three months after the THR surgery, the function of the affected limb had improved, with no lameness. Complications, such as luxation and implant failure, were not observed until 6 months after the operation. Accurate evaluation of acetabulum angles and rehearsal surgery using a 3D-printed bone model is effective for total hip replacement after unsuccessful TPO.

• Journal of Periodontal and Implant Science
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• v.42 no.5
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• pp.173-178
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• 2012

Purpose: The main purpose of this study was to investigate bone thickness on the buccal and palatal aspects of the maxillary canine and premolars using cone-beam computed tomography (CBCT). The differences between left- and right-side measurements and between males and females were also analyzed. Methods: The sample consisted of 20 subjects (9 males and 11 females; mean age, $21.9{\pm}3.0$) selected from the normal occlusion sample data in the Department of Orthodontics, The Catholic University of Korea. The thickness of the buccal and palatal bone walls, perpendicular to the long axis of the root were evaluated at 3 mm and 5 mm apical to cemento-enamel junction (CEJ) and at root apex. Results: At the canines and first premolars regions, mean buccal bone thickness of at 3 mm and 5 mm apical to CEJ were less than 2 mm. In contrast, at the second premolar region, mean buccal bone thickness at 3 mm and 5 mm apical from CEJ were greater than 2 mm. Frequency of thick bone wall (${\geq}2mm$) increased from the canine to the second premolar. Conclusions: This result should be considered before tooth extraction and planning of rehabilitation in the canine and premolar area of maxilla. Careful preoperative analysis with CBCT may be beneficial to assess local risk factors and to achieve high predictability of success in implant therapy.