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ABSTRACTMany patients and guardians prefer not to have teeth extracted as part of orthodontic treatment. Modified C-Palatal Plates (MCPPs) have been developed as an effective oral appliance. The design and procedure for placing these appliances involve a sequence of steps and specialized instruments such as a miniscrew driver. By understanding the biomechanics associated with MCPP placement, molar positioning can be optimized with less distal tipping and greater distalization. In addition to recognizing the various advantages of MCPPs, the implications of MCPPs should be considered, including the following: how far back the molars need to be moved, the effects of second and third molars in adolescents, the effects in maxillary pneumatization cases, potential impact on the airway, long-term stability, and a comparison of MCPPs to headgear. The purpose of this report is to introduce MCPP as an oral appliance that uses both miniscrews and miniplates to efficiently distalize molars minimizing the need for extraction.

Introduction. The purpose of this study was to investigate effects of surface treatment of mini-implants in diabetes-induced rabbits by comparing osseointegration around mini-implants. Methods. Twelve New Zealand white rabbits were divided into two groups (alloxan-induced diabetic group and control group). A total of 48 mini-implants were placed after four weeks of diabetic induction. 24 mini-implants were surface-treated with SLA (sandblasted with large grit, and acid etched) and the remaining 24 mini-implants had smooth surfaces. Four weeks after placement, 32 mini-implants were removed from 4 control and 4 diabetic rabbits. Insertion and removal torques were measured. The remaining 16 mini-implants from the two groups were histomorphometrically analyzed. Results. Maximum insertion torque showed no difference between diabetic and control groups, but total insertion energy was higher in control group. In surface-treated mini-implants, maximum removal torque was higher in both diabetic and control groups. Bone-implant contact (BIC) was increased in the control group when compared to the diabetic group. Surface-treated group had higher BIC than smooth surface group in both control and diabetic groups. However, there was no significantly statistical difference. Conclusions. Type 1 diabetes mellitus and surface treatment method of mini-implant affected primary stability of mini-implants. In addition, the use of orthodontic mini-implants in a diabetic patient is likely to show results similar to the healthy patient.

Objective. This study aimed to evaluate effects of type 1 diabetes mellitus and mini-implant placement method on the primary stability of mini-implants by comparing mechanical stability and microstructural/histological differences. Methods. After 4 weeks of diabetic induction, 48 mini-implants (24 self-tapping and 24 self-drilling implants) were placed on the tibia of 6 diabetic and 6 normal rabbits. After 4 weeks, the rabbits were sacrificed. Insertion torque, removal torque, insertion energy, and removal energy were measured with a surgical engine on 8 rabbits. Remaining 4 rabbits were analyzed by microcomputed tomography (micro-CT) and bone histomorphometry. Results. Total insertion energy was higher in self-drilling groups than self-tapping groups in both control and diabetic groups. Diabetic groups had more trabecular separation in bone marrow than the control groups in both SD and ST groups. Micro-CT analysis showed deterioration of bone quality in tibia especially in bone marrow of diabetic rabbits. However, there was no statistically significant correlation between self-drilling and self-tapping group for the remaining measurements in both control and diabetic groups. Conclusions. Type 1 diabetes mellitus and placement method of mini-implant did not affect primary stability of mini-implants.

Abstract The purpose of this study was to evaluate the effects of segmental osteotomy on the blood vessels and osteoclasts in rats using micro-computed tomography (micro-CT) and histomorphometric analysis. After segmental osteotomy was performed around the maxillary first molars of 36 male Sprague-Dawley rats (n = 72), the samples were divided into a control group (no displacement), 0.5 D group (0.5 mm buccal displacement) and 1.0 D group (1.0 mm buccal displacement) (n = 24/group). At 1, 2, 4 and 8 weeks after surgery, changes in the blood vessel volume were investigated using micro-CT with perfusion of radiopaque silicone rubber. Tartrate-resistant acid phosphatase (TRAP) staining was used for histomorphometric analysis. Two-way repeated measures analysis of variance (rmANOVA) was performed to compare the volume of blood vessels and number of TRAP-positive osteoclasts among the groups. Regarding blood vessel volume, the displacement groups had no significant effects, while the time points had significant effects (p = 0.014). The blood vessel volume at 1 week was significantly smaller than that at 2, 4, and 8 weeks (p = 0.004, p = 0.026, and p = 0.005, respectively). Regarding TRAP cell count, the displacement groups had no significant effects, while the time points had significant effects (p < 0.001). The number of TRAP-positive osteoclasts at 8 weeks was significantly smaller than that at 1, 2, and 4 weeks (p < 0.001, p < 0.001, and p = 0.002, respectively), and the count at 4 weeks was smaller than that at 1 week (p = 0.011). Therefore, a regional osteoclast-related acceleratory phenomenon was maintained until 4 weeks after surgery.