Long-term skeletodental changes with early and late treatment using modified C-palatal plates in hyperdivergent Class II adolescents.

OBJECTIVES: To compare skeletodental changes between early and late treatment groups using modified C-palatal plates (MCPP) and long-term retention outcomes in hyperdivergent Class II adolescents. MATERIALS AND METHODS: Seventy-one hyperdivergent Class II patients were divided into four groups according to treatment modality and treatment timing: group 1, early treatment with MCPP (n = 16; 9.9 ± 0.9 years); group 2, late treatment with MCPP (n = 19; 12.3 ± 0.8 years); group 3, early treatment with headgear (HG; n = 18; 9.6 ± 0.8 years); and group 4, late treatment with HG (n = 18; 12.1 ± 1.2 years). Lateral cephalograms were taken and skeletal and dental variables were measured. For statistical analysis, paired t-tests, independent t-tests, and multiple regression were performed. RESULTS: The early MCPP group showed a more significant decrease in mandibular plane angle than the late MCPP group did, and vertical control was more efficient in the early group than in the late group. In the MCPP groups, both FMA and SN-GoGn were increased with late treatment but decreased with early treatment, and the difference was statistically significant (P < .01). The early-treatment MCPP group had a significant decrease in SN-GoGn of 0.6° compared with an increase of 1.7° in the early treatment HG group (P < .01). Posttreatment stability of both the early and late MCPP groups was maintained in long-term retention. CONCLUSIONS: Early MCPP showed more significant vertical control than late MCPP. However, there was no difference in long-term stability between early and late groups.

Treatment effects after maxillary total arch distalization using a modified C-palatal plate in patients with Class II malocclusion with sinus pneumatization.

INTRODUCTION: The purpose of this study was to evaluate the treatment effects after molar distalization using modified C-palatal plates in patients with Class II malocclusion with maxillary sinus pneumatization. METHODS: This study consisted of 70 lateral cephalograms derived from cone-beam computerized tomography images of 35 patients with Class II malocclusion (mean age 22.3 ± 7.4 years) who had undergone bilateral total arch distalization of the maxillary dentition using modified C-palatal plates. The samples were divided into 2 groups according to sinus pneumatization; group 1 (n = 40), cephalograms with sinus pneumatization and group 2 (n = 30) cephalograms without sinus pneumatization. Paired t tests and independent-sample t tests were used to compare the changes in each group and between groups. RESULTS: The distal movement of the maxillary first molars was 4.3 mm for group 1 and 3.5 mm for group 2, with the intrusion of 1.4 mm and 2.5 mm, respectively. There was no statistically significant difference between the 2 groups. Group 1 showed 3.5° of distal tipping of the maxillary second molars, which was significantly greater than the 0.2° in group 2 (P <0.05). The total treatment period, including distalization, was 2.2 years for group 1 and 1.9 years for group 2, but the difference was not significant. CONCLUSIONS: There was no significant difference in the amount of distal movement and intrusion of the maxillary first molars between groups 1 and 2. Therefore, these results suggest that regardless of sinus pneumatization, molar distalization using temporary skeletal anchorage devices in Class II patients can be performed as a nonextraction treatment.

The effects of a corticotomy on space closure by molar protraction using TSADs in patients with missing mandibular first molars.

INTRODUCTION: The purpose of this study was to evaluate the effects of a triangular-shaped corticotomy on the protraction of second and third molars in patients with missing mandibular first molars. SUBJECTS AND METHODS: The corticotomy and non-corticotomy groups consisted of sixteen first molars in fifteen patients (28.6 ± 9.4 years) and nineteen first molars in fifteen patients (26.6 ± 8.4 years), respectively. A triangular-shaped corticotomy was performed between the second premolar and molar. Temporary skeletal anchorage devices (TSADs) were placed between the first and second premolars in both groups. Mandibular dentition variables were measured on the pre and post-treatment panoramic radiographs and lateral cephalograms. Analysis of covariance was performed. RESULTS: The corticotomy group exhibited 2.8 mm more inter-radicular correction between the second molar to second premolar roots (P < .001) and 1.6 mm more inter-radicular distance correction between the third molar to second premolar roots compared to the non-corticotomy group (P < .01). The corticotomy group required 5.5 months less treatment time for space closure (P < .05), but the total treatment time was the same for both groups. CONCLUSIONS: The inter-radicular distance between the mandibular second premolar and molar and treatment times for space closure was significantly reduced in the corticotomy group.

Total maxillary arch distalization with modified C-palatal plates in adolescents: A long-term study using cone-beam computed tomography.

INTRODUCTION: The aims of this study were to evaluate the long-term skeletodental effects, the volume of maxillary tuberosity, and airway space changes after maxillary molar distalization using modified C-palatal plate (MCPP) in adolescents with Class II malocclusion. METHODS: The sample consisted of 20 adolescent patients (MCPP group; mean age, 12.9 ± 1.0 year) who underwent bilateral distalization of their maxillary dentition and 20 subjects as a control group. In the MCPP group, cone-beam computed tomography images were taken before distalization, at the end of the treatment, and during retention with a minimum of a 3-year posttreatment follow up period. Repeated measures ANOVA followed by post-hoc analysis with the Bonferroni test were used to identify significant differences between time points. RESULTS: After the long-term observation period, sagittal skeletal and dental relationships were maintained (there were no significant changes in ANB, occlusal plane angle, and overjet postretention). The vertical skeletal dimension did not change during treatment and was stable at the long-term follow-up (the mandibular plane angle and ANS-Me were relatively well maintained). The volume of the maxillary tuberosity showed no significant change during long-term retention. However, the volume was significantly smaller in the treatment group than in the control group (P <0.0001). There were no significant airway space changes after distalization and the postretention period. In addition, there was no significant difference between the MCPP and control groups. CONCLUSIONS: Improved sagittal skeletal and dental relationships because of treatment were maintained in the long-term evaluation. There was no negative long-term effect on airway space associated with the maxillary arch distalization. Therefore, these findings might be beneficial for clinicians in diagnosis and treatment planning for Class II malocclusion in adolescents.

Zinc-coated carbonate apatite derived from avian eggshell for potential use as bone substitute. Part I: preparation and properties.

PURPOSE: To develop antibacterial bone substitutes derived from avian eggshell using microwave processing to convert natural calcium carbonate (CaCO3) into zinc-coated carbonate apatite (CHA). METHODS: Zinc-coated carbonate apatite was prepared using domestic microwave and then characterized with scanning electron microscopy (SEM), x-ray diffraction (XRD), Fourier transform infrared spectroscopy (FT-IR), and energy dispersive x-ray analysis (EDXA). The trial animal study was conducted by filling different bone substitutes into 5-mm-diameter standard defects on the parietal bone of New Zealand rabbits to observe new bone formation for 8 weeks. RESULTS: SEM, XRD, FT-IR, and EDXA confirmed characteristics of zinc-coated CHA derived from avian eggshell using microwave method. Histological analysis demonstrated that the defects filled with carbonate apatite had more calcified bone and less uncalcified bone formation than other groups. CONCLUSIONS: The present research demonstrated the efficient use of microwave in the conversion of natural CaCO3 into CHA with zinc coating. The examined properties showed the potential use of the new material as an antibacterial bone substitute in oral surgery. The trial animal study implied favorable osteoconductive ability of carbonate apatite in new bone formation.

Improved biocompatibility of hydroxyapatite thin film prepared by aerosol deposition.

Technical development for an efficient coating of bioactive materials improves the characteristics of a fully functional implant. The aim of this study was to investigate the osteoinductive effect of a newly developed hydroxyapatite (HA)-coating technique using aerosol deposition without post-heat treatment [room temperature (RT) group] on the titanium (Ti) dental implant in vitro and in vivo, compared with that of HA coating with post-heat treatment (HT-400 group) or machined surface (control group). Cell proliferation or attachment on the HA-coated Ti surface was assessed using tetrazolium salt, WST-8 or scanning electron microscopy (SEM). Human osteoblasts (HOB) on RT group were well attached and grew alike in the control or HT-400 group. The alkaline phosphatase activity of HOB cultured on RT and HT-400 group was significantly higher than the control group (p < 0.05). Evaluation by SEM, TEM, and XRD demonstrated that aerosol deposition facilitated HA particles to form a dense and uniform HA layer in the RT group despite no post-heating. In a rabbit tibia model (n = 3), the ratios of bone implant contact and bone area in the RT group (49.88%, 86.05%) were greater than in the HT-400 group (38.82%, 77.34%) or the control (28.31%, 73.86%). The finding of this study showed that the HA coating using aerosol deposition without post-heat treatment has a good biocompatibility, and provide a promoting strategy to enhance osseointegration in the application of the dental implant.

Nonwoven silk fibroin net/nano-hydroxyapatite scaffold: preparation and characterization.

The purpose of this study was to prepare and characterize a three-dimensional scaffold consisting of porous nonwoven silk fibroin net/nano-apatite composite. The silk fibroin net was mineralized with apatite by alternative soaking in calcium and phosphate solutions. The scaffold exhibited a porous microstructure with open porosity (70-78%), with an average pore size of about 163 +/- 40.0 microm. The swelling ratio and water uptake were 4.55% and 81.93%, respectively, indicating excellent hydrophilicity. The nano-sized hydroxyapatite crystals were needle like, with a length of approximately 100-300 nm and a diameter of approximately 20-60 nm. The results of in vitro cell culture study using rat osteoblast cells demonstrated that the nonwoven silk fibroin net/nano-apatite composite showed excellent cytocompatibility for the growth of osteoblasts and had the capability to improve the viability of osteoblasts.

Antibacterial effect of zinc phosphate mineralized guided bone regeneration membranes.

PURPOSE: Current commercial guided bone regeneration membranes are susceptible to bacterial colonization, leading to premature membrane degradation. The purpose of this research is to modify current resorbable guided bone regeneration membranes with antibacterial property by mineralizing with zinc phosphate. MATERIALS: Resolut Adapt LT (Gore-Tex; W.L. Gore & Associates, Inc., Flagstaff, AZ), composed of copolymer PGA/TMC, and BioMend Extend (Zimmer Dental, Carlsbad, CA), composed of bovine type 1 collagen, were used. The membranes were mineralized with zinc phosphate. The mineralized membranes were characterized using scanning electron microscopy, energy dispersive spectroscopy, x-ray diffraction, Fourier transform infrared spectroscopy, inductive coupled plasma, and thermogravimetry. Antibacterial property of zinc phosphate mineralized and nonmineralized membranes were determined using Actinobacillus actinomycetemcomitans standard strain ATCC 29522. RESULTS: Scanning electron microscopy, energy dispersive system, and Fourier transform infrared identified zinc phosphate in the zinc phosphate mineralized membranes. Zinc phosphate mineralized membranes showed significant reduction in bacterial colony, forming units compared to nonmineralized membranes. CONCLUSION: Results of this study suggest that the use of zinc phosphate mineralized membranes can inhibit oral bacterial colonization and prevent inflammation due to membrane exposure. This antibacterial property may help achieve the optimal goal of guided bone regeneration.

Treatment algorithm for locally recurrent osteosarcoma based on local disease-free interval and the presence of lung metastasis.

BACKGROUND: Local recurrence in osteosarcoma is clinically distinct from metastasis, although associated with a similar reduction in survival. The prognostic factors in locally recurrent osteosarcoma were investigated and these factors were translated into a management strategy. METHODS: In all, 407 consecutive patients with skeletal osteosarcoma between 1977 and 2002 were analyzed. Twenty-three patients with resectable local recurrence were analyzed. Clinical and tumor-related factors were assessed for significance in relation to survival and a management strategy was formulated based on factors found to be independently significant for survival. RESULTS: Seventeen of the 23 patients underwent primary resections and initial treatment, yielding an overall local recurrence rate of 4.2% for resectable cancer. Median time to local recurrence was 13 months (95% confidence interval, 9-16 months). The 5-year and 10-year survival rates in the recurrent cases were 29% and 10%, respectively. All patients received chemotherapy both for their primary and recurrent disease. Increased risk of local recurrence (P < .0001) was strongly correlated with positive margins of resection. The rate of local recurrence was not related to chemotherapy-associated necrosis in the primary tumor. Nevertheless, neoadjuvant therapy halved the risk of local recurrence (odds ratio, 1.92; P = .3, power 10%). The strongest correlate with poor survival was local recurrence within the first year after primary resection (P = .001), followed by metastasis at the time of first local recurrence (P = .04) and failure to achieve clinical remission after disease recurrence (P = .04). Chemotherapy-associated necrosis and margins of resection of the primary tumor were not significant prognostic variables for survival. Survival differed significantly among patients defined by local disease-free interval and lung metastasis (P = .0001). They required an individualized approach as captured in the management algorithm. CONCLUSION: There is a residual risk of local recurrence in patients despite favorable chemotherapy-associated necrosis and negative margins of resection. A treatment strategy emphasizing clinical remission at all identifiable sites offers the highest likelihood of survival in this patient population.