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Browsing by Author "Deguchi, Toru"
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Item CBCT of skeletal changes following rapid maxillary expansion to increase arch-length with a development-dependent bonded or banded appliance(Allen Press, 2013) Kanomi, Ryuzo; Deguchi, Toru; Kakuno, Eriko; Takano-Yamamoto, Teruko; Roberts, W. Eugene; Orthodontics and Oral Facial Genetics, School of DentistryObjective: To assess the three-dimensional (3D) skeletal response to a standardized 5 mm of rapid maxillary expansion (RME) in growing children (6-15 years) with maxillary width deficiency and crowding. Materials and methods: A bonded appliance was used prior to the eruption of the maxillary first premolars (Mx4s), and a banded appliance was used thereafter. A consecutive sample of 89 patients (29 boys and 60 girls) from a large pediatric dentistry and orthodontics practice was divided into four groups: 1) 6-8 years old (n = 26), 2) 9-11 years old with unerupted Mx4s (n = 21), 3) 9-11 years with erupted Mx4s (n = 23), and 4) 12-15 years (n = 19). For all patients, the 3D evaluation of dental and skeletal effects was performed with cone-beam computed tomography (CBCT). Results: For both appliances in all patients, CBCT confirmed a triangular pattern of expansion in both the frontal and sagittal planes. Overall, both appliances produced significant maxillary expansion (>80% of the 5-mm activation), but older children showed a progressively more dental (less skeletal) response. Comparison of the two types of expanders in the crossover sample, children aged 9-11 years, showed that the bonded RME produced the most efficient skeletal expansion in the preadolescent sample. Increased maxillary width at the level of the zygomaticomaxillary suture was the best indicator for development of maxillary arch circumference. Conclusion: Development-dependent appliances (bonded RPE before Mx4s erupt, and a banded device thereafter) provided optimal RME treatment for all children from age 6-15 years.Item Decreased alveolar bone turnover is related to the occurrence of root resorption during experimental tooth movement in dogs(2015) Deguchi, Toru; Seiryu, Masahiro; Daimaruya, Takayoshi; Garetto, Lawrence P.; Takana-Yamamoto, Teruko; Roberts, W. Eugene; Department of Oral Pathology, Medicine and Radiology, IU School of DentistryObjective: To investigate the relationship between root resorption (RR) and bone turnover in two different types of tooth movement in dogs. Materials and Methods: A total of 16 dogs in two different groups were used. Tooth movement of dog premolars resulted from approximately 200 g of force. Histomorphometric analysis of premolar roots was assessed after 4 and 12 weeks of tooth movement by comparing nonresorptive to resorptive surfaces. Results: Histomorphometric analysis indicated a significant decrease in the bone formation rate in the root resorptive areas, which resulted in decreased bone volume after 12 weeks. The threshold to detect RR in periapical radiographs was about 1.0 mm2. Conclusions: A sustained mechanical load, due to the prolonged stress and strain of continuous mechanics, induces elevated bone metabolic activity, such as the bone turnover (remodeling) and change in bone volume (modeling). Therefore, our data support the hypothesis that increased RR is related to decreased bone formation (turnover) in high stress areas exposed to prolonged orthodontic tooth movement.Item Miniature Implants for Orthodontic Anchorage(2001) Deguchi, Toru; Garetto, Lawrence P.; Katona, Thomas R.; Hohlt, Thomas R.; Roberts, W. Eugene; Shanks, James C.Anchorage control is fundamental to successful orthodontic treatment. Dental implants can serve as ideal anchorage units because of their stability in bone. Previous studies limit the use of existing implants for anchorage because of their large size. Minimizing the size of the implant would reduce the extent of the surgery and may result in a decreased and less traumatic healing period. The objective of this study was to histomorphometrically analyze the use of miniature implants. A total of 96 miniature implants (1.0 x 5.0 mm; 48 loaded and 48 healing control) were placed in the mandible and maxilla of 8 male dogs. The implants were allowed to heal for three different periods (3, 6, and 12 weeks) followed by 12 weeks of 200 to 300 g of orthodontic force application. Bone specimens containing implants were collected for histomorphometric analysis. The results indicate that clinical rigidity (osseointegration) was achieved by 96.9 percent of the miniature implants. Histomorphometric analysis revealed that the amount of bone contact at the implant-bone interface ranged from 11.3 to 68 percent (mean ± SEM=34.4 ± 4.6 percent) in the healing control groups and from 18.8 to 63 percent (mean=43.l ± 4.0 percent) in the force applied groups in the maxilla. On the other hand, in the mandible, bone-implant contact ranged from 7 to 82 percent (mean=44.1 ± 6.8 percent) in the healing control groups and from 12 to 72 percent (mean=50.7 ± 5.3 percent) in the force applied groups. Results from bone formation rate, mineralizing surface/bone surface and mineral appositional rate showed a significant difference in the 3-week healing control group compared to those in other groups. From these results, we concluded that miniature implants are able to function as rigid osseous anchorage for orthodontics with minimal (less than 3 weeks) healing period. This study was supported by Matsumoto Research fund.