ABSTRACT
OBJECTIVE: To evaluate the three-dimensional (3D) stability and accuracy of additively manufactured surgical templates fabricated using two different 3D printers and materials. MATERIALS AND METHODS: Forty surgical templates were designed and printed using two different 3D printers: the resin group (n = 20) used a digital light processing (DLP) 3D printer with photopolymer resin, and the metal group (n = 20) employed a selective laser melting (SLM) 3D printer with titanium alloy. All surgical templates were scanned immediately after production and re-digitalized after one month of storage. Similarly, the implant simulations were performed twice. Three-dimensional congruency between the original design and the manufactured surgical templates was quantified using the root mean square (RMS), and the definitive and planned implant positions were determined and compared. RESULTS: At the postproduction stage, the metal templates exhibited higher accuracy than the resin templates (p < 0.001), and these differences persisted after one month of storage (p < 0.001). The resin templates demonstrated a significant decrease in three-dimensional stability after one month of storage (p < 0.001), whereas the metal templates were not affected (p > 0.05). No significant differences in implant accuracy were found between the two groups. However, the resin templates showed a significant increase in apical and angular deviations after one month of storage (p < 0.001), whereas the metal templates were not affected (p > 0.05). CONCLUSION: Printed metal templates showed higher fabrication accuracy than printed resin templates. The three-dimensional stability and implant accuracy of printed metal templates remained unaffected by one month of storage. CLINICAL SIGNIFICANCE: With superior three-dimensional stability and acceptable implant accuracy, printed metal templates can be considered a viable alternative technique for guided surgery.
Subject(s)
Printing, Three-Dimensional , Titanium , Humans , Titanium/chemistry , Computer-Aided Design , Lasers , Dental Implants , Alloys/chemistry , Imaging, Three-Dimensional/methods , Dental Implantation, Endosseous/instrumentation , Dental Implantation, Endosseous/methods , Dental Materials/chemistry , Dental Alloys/chemistry , Materials TestingABSTRACT
OBJECTIVES: To introduce a modified guided bone regeneration (GBR) technique using intact periosteum and deproteinized bovine bone mineral (DBBM) for peri-implant augmentation and compare the clinical outcomes with those of conventional GBR. MATERIALS AND METHODS: Patients who received peri-implant augmentation in posterior sites between 2015 and 2021 were reviewed in this study. Group A was treated with a modified GBR technique, and Group B was treated with conventional GBR. For group comparison, propensity score matching was performed with a sensitivity analysis. The implant survival rate, dimensional changes in hard tissue, marginal bone loss (MBL), and peri-implant parameters were evaluated. RESULTS: In total, 114 implants from 98 patients were included. The implant survival rates were 95.74% in Group A and 95.00% in Group B during the follow-up period. At 6 months, the median horizontal thickness was recorded at 0.87 mm (IQ1-IQ3 = 0.00-1.75 mm) in Group A, exhibiting a relatively lower value compared to the corresponding measurement of 0.98 mm (IQ1-IQ3 = 0.00-1.89 mm) in Group B (p = .937). Vertical height displayed no statistically significant intergroup difference between the two groups (p = .758). The mean follow-up period was 25.83 ± 12.93 months after loading in Group A and 27.47 ± 21.29 months in Group B (p = .761). MBL and peri-implant parameters were comparable between the two groups. CONCLUSIONS: Within the limitations of this study, the modified GBR technique using intact periosteum and DBBM grafting might be a viable alternative to correct bone defects around implants in molar and premolar sites.
Subject(s)
Bone Regeneration , Guided Tissue Regeneration, Periodontal , Humans , Retrospective Studies , Female , Male , Middle Aged , Follow-Up Studies , Adult , Guided Tissue Regeneration, Periodontal/methods , Dental Implantation, Endosseous/methods , Periosteum/surgery , Alveolar Ridge Augmentation/methods , Alveolar Bone Loss/surgery , Treatment Outcome , Aged , Dental ImplantsABSTRACT
OBJECTIVE: To study the prevalence of cerebral palsy (here in after referred to CP) in children aged 1 - 6 in Guangxi, China, and its epidemiologic characteristics and relevant risk factors. METHODS: Investigations on the prevalence and etiology of CP in children at ages of 1 - 6 were conducted in Nanning, Hengxian and Qinzhou of Guangxi from June to December in 1998, with a cluster sampling. RESULTS: Totally, 150 806 children aged 1 - 6 were investigated in Nanning, Hengxian and Qinzhou of Guangxi, with 89 418 boys and 61 388 girls. Among them, 193 children were diagnosed as CP, with a prevalence rate of 1.28 per thousand, higher in boys (136 cases, 1.52 per thousand ) than in girls (57 cases, 0.93 per thousand ), with statistical significance (chi(2) = 9.536 7, P = 0.02). Logistic regression analysis showed that risk factors for CP were children who could not cry after birth (neonatal asphyxia), Apgar score less than eight, delivery at lower level of maternity hospital, number of mother's gravidity, no prenatal checks for mothers, and taking antipyretics and preserved food with salt during pregnancy. CONCLUSIONS: Prevalence of CP in children of Guangxi was at a lower level in comparison with that in other areas at home and abroad, which, maybe, was related with the lower neonatal survival and higher infant mortality.
