Standardized multi-institutional data analysis of fixed and removable prosthesis: estimation of life expectancy with regards to variable risk factors.

PURPOSE: This study aims to assess and predict lifespan of dental prostheses using newly developed Korean Association of Prosthodontics (KAP) criteria through a large-scale, multi-institutional survey. MATERIALS AND METHODS: Survey was conducted including 16 institutions. Cox proportional hazards model and principal component analysis (PCA) were used to find out relevant factors and predict life expectancy. RESULTS: 1,703 fixed and 815 removable prostheses data were collected and evaluated. Statistically significant factors in fixed prosthesis failure were plaque index and material type, with a median survival of 10 to 18 years and 14 to 20 years each. In removable prosthesis, factors were national health insurance coverage, antagonist type, and prosthesis type (complete or partial denture), with median survival of 10 to 13 years, 11 to 14 years, and 10 to 15 years each. For still-usable prostheses, PCA analysis predicted an additional 3 years in fixed and 4.8 years in removable prosthesis. CONCLUSION: Life expectancy of a prosthesis differed significantly by factors mostly controllable either by dentist or a patient. Overall life expectancy was shown to be longer than previous research.

Photobiomodulation-Based Synergic Effects of Pt-Coated TiO2 Nanotubes and 850 nm Near-Infrared Irradiation on the Osseointegration Enhancement: In Vitro and In Vivo Evaluation.

Photobiomodulation (PBM) therapy is known to have the potential to improve bone regeneration after implant surgery. However, the combinatory effect of the nanotextured implant and PBM therapy on osseointegration has not yet been proved. This study evaluated the photobiomodulation-based synergistic effects of Pt-coated titania nanotubes (Pt-TiO2 NT) and 850 nm near-infrared (NIR) light on osteogenic performance in vitro and in vivo. The FE-SEM and the diffuse UV-Vis-NIR spectrophotometer were used to perform the surface characterization. The live-dead, MTT, ALP, and AR assays were tested to perform in vitro tests. The removal torque testing, the 3D-micro CT, and the histological analysis were used to conduct in vivo tests. The live-dead and MTT assay resulted in Pt-TiO2 NTs being biocompatible. The ALP activity and AR assays demonstrated that the combination of Pt-TiO2 NT and NIR irradiation significantly enhanced osteogenic functionality (p < 0.05). The results of in vivo test, employing the removal torque testing, the 3D-micro CT, and histological analysis, showed overall improved outcomes; however, no significant difference was observed between the control and experimental groups (p > 0.05). Therefore, we confirmed the possibility of the combination of Pt-TiO2 NT and NIR light as a promising technology for implant surgery in dentistry.

Enhanced Bone Formation by Rapidly Formed Bony Wall over the Bone Defect Using Dual Growth Factors.

BACKGROUND: In guided bone regeneration (GBR), there are various problems that occur in the bone defect after the wound healing period. This study aimed to investigate the enhancement of the osteogenic ability of the dual scaffold complex and identify the appropriate concentration of growth factors (GF) for new bone formation based on the novel GBR concept that is applying rapid bone forming GFs to the membrane outside of the bone defect. METHODS: Four bone defects with a diameter of 8 mm were formed in the calvaria of New Zealand white rabbits each to perform GBR. Collagen membrane and biphasic calcium phosphate (BCP) were applied to the bone defects with the four different concetration of BMP-2 or FGF-2. After 2, 4, and 8 weeks of healing, histological, histomorphometric, and immunohistochemical analyses were conducted. RESULTS: In the histological analysis, continuous forms of new bones were observed in the upper part of bone defect in the experimental groups, whereas no continuous forms were observed in the control group. In the histomorphometry, The group to which BMP-2 0.5 mg/ml and FGF-2 1.0 mg/ml was applied showed statistically significantly higher new bone formation. Also, the new bone formation according to the healing period was statistically significantly higher at 8 weeks than at 2, 4 weeks. CONCLUSION: The novel GBR method in which BMP-2, newly proposed in this study, is applied to the membrane is effective for bone regeneration. In addition, the dual scaffold complex is quantitatively and qualitatively advantageous for bone regeneration and bone maintenance over time.

Improving Bone Formation by Guided Bone Regeneration Using a Collagen Membrane with rhBMP-2: A Novel Concept.

We examined whether recombinant human bone morphogenetic protein-2 (rhBMP-2) when applied to collagen membranes, would reinforce them during guided bone regeneration. Four critical cranial bone defects were created and treated in 30 New Zealand white rabbits, including a control group, critical defect only; group 1, collagen membrane only; group 2, biphasic calcium phosphate (BCP) only; group 3, collagen membrane + BCP; group 4, collagen membrane with rhBMP-2 (1.0 mg/mL); group 5, collagen membrane with rhBMP-2 (0.5 mg/mL); group 6, collagen membrane with rhBMP-2 (1.0 mg/mL) + BCP; and group 7, collagen membrane with rhBMP-2 (0.5 mg/mL) + BCP. After a 2-, 4-, or 8-week healing period, the animals were sacrificed. The combination of collagen membranes with rhBMP-2 and BCP yielded significantly higher bone formation rates compared to the other groups (control group and groups 1-5 < groups 6 and 7; p < 0.05). A 2-week healing period yielded significantly lower bone formation than that at 4 and 8 weeks (2 < 4 = 8 weeks; p < 0.05). This study proposes a novel GBR concept in which rhBMP-2 is applied to collagen membranes outside instead of inside the grafted area, thereby inducing quantitatively and qualitatively enhanced bone regeneration in critical bone defects.

Evaluation of the machinability and machining accuracy of polymer-based CAD/CAM blocks using merlon fracture test model.

The aims of this study were to estimate the machinability and machining accuracy of polymer-based CAM blocks using the merlon fracture test model specified in ISO 18675: 2022. Three hybrid disc blanks (MazicDuro, HC Disk, and Enamic) and three polymethyl methacrylate (PMMA) disc blanks (PMMA Disk, PMMA Block, and MazicTemp Hybrid) were tested in this study. The machinability was evaluated by assigning scores according to the fracture range of merlons with areas divided by ten vertical planes. The machining accuracy was evaluated by superimposing methods via CAD reference data and CAD specimen data. Within the limits of this study, a thickness of 0.3 mm is recommended for the clinical application of polymer-based CAD/CAM blocks in dental restorations that require superior machinability and accuracy. In addition, the machinability and machining accuracy tests of polymer-based CAM blocks are expected to provide guidelines for preparing accurate dental restorations.

Hydrothermally treated coral scaffold promotes proliferation of mesenchymal stem cells and enhances segmental bone defect healing.

Introduction: Synthetic hydroxyapatite (HAp) scaffolds have shown promising therapeutic outcomes in both animals and patients. In this study, we aim to evaluate the chemical and physical phenotype, biocompatibility, and bone repair effects of hydrothermally treated coral with natural coral and synthetic HAp. Methods: The phase composition, surface pattern, 3D structures, and porosity of the scaffolds were characterized, and cell viability, proliferation, and osteogenic differentiation of mesenchymal stem cells (MSCs) after seeding onto the scaffold were determined. The scaffolds were implanted into rats to assess their bone repair effects using micro-CT analysis, mechanical testing, and histological staining. Results: The results showed that the phase composition, porous structure, and porosity of hydrothermally treated coral were comparable to pure HAp scaffold. While only the natural coral happens to be dominantly calcium carbonate. Higher cell proliferation and osteogenic differentiation potential were observed in the hydrothermally treated coral scaffold compared to natural coral and pure HAp. Histological results also showed increased new bone formation in the hydrothermally treated coral group. Discussion: Overall, our study suggests that hydrothermal modification enhances the cytocompatibility and therapeutic capacity of coral without altering its physical properties, showing superior effectiveness in bone repair to synthetic HAp.

A Comparative Study of Additive and Subtractive Manufacturing Techniques for a Zirconia Dental Product: An Analysis of the Manufacturing Accuracy and the Bond Strength of Porcelain to Zirconia.

This study was aimed at preparing zirconia samples via additive manufacturing (AM) and subtractive manufacturing (SM) and testing the following aspects: (1) the manufacturing accuracy of the zirconia samples and (2) the bond strength of porcelain to zirconia to evaluate the applicability of the zirconia fabricated by AM in dental clinics. We used three milling machines for SM (AR, K5, and UP) and a 3D printer for AM (AO). The manufacturing accuracy of the zirconia specimen in the internal and marginal areas was evaluated by superimposing techniques to calculate the root mean square (RMS) values. The bond strengths of porcelain to zirconia prepared via SM and AM were measured using a universal testing machine. The internal and marginal RMS values of the zirconia prepared by AM (AO) were within the range of those of the zirconia prepared by SM (AR, K5, and UP). Moreover, the bond strength value of the zirconia prepared by AM (35.12 ± 4.09 MPa) was significantly higher than that of the zirconia prepared by SM (30.26 ± 5.20 MPa). Therefore, AM technology has significant potential for applications in dentistry.

Dual Delivery of BMP2 and IGF1 Through Injectable Hydrogel Promotes Cranial Bone Defect Healing.

Critical-sized cranial bone defect remains a great clinical challenge. With advantages in regenerative medicine, injectable hydrogels incorporated with bioactive molecules show great potential in promoting cranial bone repair. Recently, we developed a dual delivery system by sequential release of bone morphogenetic protein 2 (BMP2) followed by insulin-like growth factor 1 (IGF1) in microparticles (MPs), and an injectable alginate/collagen (alg/col)-based hydrogel. In this study, we aim to evaluate the effect of dual delivery of BMP2 and IGF1 in MPs through the injectable hydrogel in critical-sized cranial bone defect healing. The gelatin MPs loaded with BMP2 and poly(lactic-co-glycolic acid)-poly(ethylene glycol)-carboxyl (PLGA-PEG-COOH) MPs loaded with IGF1 were prepared, respectively. The encapsulation efficiency and release profile of growth factors in MPs were measured. A cranial defect model was applied to evaluate the efficacy of the dual delivery system in bone regeneration. Adult Sprague Dawley rats were subjected to osteotomy to make an ⌀8-mm cranial defect. The injectable hydrogel containing MPs loaded with BMP2 (2 µg), IGF1 (2 µg), or a combination of BMP2 (1 µg) and IGF1 (1 µg) were injected to the defect site. New bone formation was evaluated by microcomputed tomography, histological analysis, and immunohistochemistry after 4 or 8 weeks. Data showed that dual delivery of the low-dose BMP2 and IGF1 in MPs through alg/col-based hydrogel successfully restored cranial bone as early as 4 weeks after implantation, whose effect was comparable to the single delivery of high-dose BMP2 in MPs. In conclusion, this study suggests that dual delivery of BMP2 and IGF1 in MPs in alg/col-based hydrogel achieves early bone regeneration in critical-sized bone defect, with advantage in reducing the dose of BMP2. Impact Statement Sequential release of bone morphogenetic protein 2 (BMP2) followed by insulin-like growth factor 1 (IGF1) in two different microparticles promotes critical-sized bone defect healing. This dual delivery system reduces the dose of BMP2 by supplementing IGF1, which may diminish the potential side effects of BMP2.

Visible Light-Mediated Sustainable Antibacterial Activity and Osteogenic Functionality of Au and Pt Multi-Coated TiO2 Nanotubes.

The visible light reactions of noble metal-based photocatalysts have been increasingly utilized to investigate their antibacterial activities. Furthermore, the photoreactions at various visible light wavelengths for specific combinations of titania nanotubes and noble metal nanoparticles have been found to promote osteogenic functionality. In this investigation, a novel multi-coating combination of noble metals (gold and platinum) on titania nanotubes was assessed using plasmonic photocatalysis and low-level laser therapy at 470 and 600 nm. The results showed that this coating on the nanotubes promoted antibacterial activity and osteogenic functionality. The order in which the gold and platinum coatings were layered onto the titania nanotubes strongly affected the osteogenic performance of the human mesenchymal stem cells. These results have identified a new approach for the development of efficient novel combinations of noble metal nanoparticles and titania nanotubes with visible light responses, sustainable antimicrobial activity, and osteogenic functionality.

Immediate loading protocols increase the risk of failure of implants placed by fully guided surgery in partially edentulous jaws: A randomized clinical trial.

AIM: To compare the 1-year outcomes of immediate loading (IL) and delayed loading (DL) protocols for implants placed by fully guided surgery in partially edentulous jaws. MATERIALS AND METHODS: This study included 72 patients who received implant surgery with either IL (93 implants, 36 patients) or DL (94 implants, 26 patients). A prefabricated provisional prosthesis was delivered immediately for the IL group (86 implants, 32 patients) with the exception of 4 subjects in whom an initial torque of >20 Ncm and an implant stability quotient of >65 were not achieved, while all DL-group implants were loaded after 3 months. The 1-year implant survival rate estimated by intention-to-treat (ITT) and per-protocol (PP) analyses, and the marginal bone loss (MBL) estimated by cone-beam computed tomography were statistically evaluated (p < 0.05). RESULTS: The survival rate in the DL group was 100% at both patient and implant levels. With only 26 subjects with 78 implants surviving in the IL group, the survival rates were 69.4% and 83.4% at the patient and implant levels, respectively, in the ITT analysis, and 78.1% and 90.2% in the PP analysis. All intergroup differences in survival rates were statistically significant (p < 0.01). MBL was less than 0.1 mm in both groups (p > 0.05). CONCLUSIONS: IL for implants placed by fully guided surgery in the partially edentulous jaws increased the probability of failure compared to 3-month DL. Regardless of when loading occurred, marginal bone levels remained stable.

Effect of Acid Mixtures on Surface Properties and Biaxial Flexural Strength of As-Sintered and Air-Abraded Zirconia.

The aim of this work was to evaluate the effects of application time of an acid mixture solution on the surface roughness, phase transformation, and biaxial flexural strength of 3Y-TZP after sintering or air abrasion. For the biaxial flexural strength measurement, 220 3Y-TZP disk-shaped specimens were prepared after as-sintering or air abrasion. The etching solution comprised a mixture of hydrofluoric acid, sulfuric acid, hydrogen peroxide, methyl alcohol, and purified water. The samples were divided into 11 subgroups according to the etching times (Control, 1, 2, 3, 5, 8, 10, 12, 15, 20, and 30 min). The results showed that acid treatment on both as-sintered and air-abraded 3Y-TZP surfaces increased the surface roughness. However, it had no significant effects on the monoclinic phase or flexural strength of as-sintered zirconia. The monoclinic phase and flexural strength of air-abraded zirconia increased sharply after air abrasion; however, they gradually decreased after acid treatment, to a similar level to the case of the untreated surface. Surface treatment with acid mixture increased the roughness, but the lack of increase of monoclinic phase is thought to be because the loose monoclinic particles remaining on the surface were removed through the etching process.

Effects of Postcuring Temperature on the Mechanical Properties and Biocompatibility of Three-Dimensional Printed Dental Resin Material.

Three-dimensional (3D) printing is an attractive technology in dentistry. Acrylic-based 3D printed resin parts have to undergo postcuring processes to enhance their mechanical and biological properties, such as UV-light and thermal polymerization. However, no previous studies have revealed how the postcuring temperature influences the biocompatibility of the produced parts. Therefore, we postprocessed 3D printed denture teeth resin under different postcuring temperatures (40, 60 and 80 °C) for different periods (15, 30, 60, 90 and 120 min), and evaluated their flexural properties, Vickers hardness, cell cytotoxicity, cell viability, and protein adsorption. In addition, confocal laser scanning was used to assess the condition of human gingival fibroblasts. It was found that increasing the postcuring temperature significantly improved the flexural strength and cell viability. The flexural strength and cell viability were 147.48 ± 5.82 MPa (mean ± standard deviation) and 89.51 ± 7.09%, respectively, in the group cured at 80 °C for 120 min, which were higher than the values in the 40 and 60 °C groups. The cell cytotoxicity increased in the 40 °C groups and for longer cultivation time. Confocal laser scanning revealed identifiable differences in the morphology of fibroblasts. This study has confirmed that the postcuring temperature influences the final mechanical and biological properties of 3D printed resin.

Osseointegration of Plasma Jet Treated Titanium Implant Surface in an Animal Model.

Osseointegration of titanium implant is important for the success of both dental and medical implants. Previous studies have attempted to improve osseointegration by considering the use of plasma jet technology, where information with animal models and parameters related to osseointegration is still lacking. Therefore, this study investigated the effects of non-thermal atmospheric pressure plasma jet (NTAPPJ) treatment on titanium implants in terms of osseointegration in mongrel dogs. A total of 41 implants; 21 NTAPPJ treated and 20 control, were placed in the maxilla and mandible of six mongrel dogs for either 4 or 8 weeks. The bone volume (BV) and bone-to-implant contact (BIC) ratio were determined by region of interest (ROI). Statistical analysis was performed with the Wilcoxon rank-sum test. The NTAPPJ group at 4 weeks showed higher numbers in both BV and BIC (p < 0.05) compared to the control group. However, at 8 weeks there were less significant differences between the control or experimental group as the control group had caught up with the experimental group. Hence, NTAPPJ may be an effective treatment for the initial healing period which is critical to ensure reliable long-term predictability. The BV and BIC have been clinically proven to accelerate in the initial stages with the use of NTAPPJ to aid in the healing and initial stability of implants.

In Vivo Study for Clinical Application of Dental Stem Cell Therapy Incorporated with Dental Titanium Implants.

The aim of this study was to investigate the behavior of dental-derived human mesenchymal stem cells (d-hMSCs) in response to differently surface-treated implants and to evaluate the effect of d-hMSCs on local osteogenesis around an implant in vivo. d-hMSCs derived from alveolar bone were established and cultured on machined, sandblasted and acid-etched (SLA)-treated titanium discs with and without osteogenic induction medium. Their morphological and osteogenic potential was assessed by scanning electron microscopy (SEM) and real-time polymerase chain reaction (RT-PCR) via mixing of 5 × 106 of d-hMSCs with 1 mL of Metrigel and 20 µL of gel-cell mixture, which was dispensed into the defect followed by the placement of customized mini-implants (machined, SLA-treated implants) in New Zealand white rabbits. Following healing periods of 2 weeks and 12 weeks, the obtained samples in each group were analyzed radiographically, histomorphometrically and immunohistochemically. The quantitative change in osteogenic differentiation of d-hMSCs was identified according to the type of surface treatment. Radiographic analysis revealed that an increase in new bone formation was statistically significant in the d-hMSCs group. Histomorphometric analysis was in accordance with radiographic analysis, showing the significantly increased new bone formation in the d-hMSCs group regardless of time of sacrifice. Human nuclei A was identified near the area where d-hMSCs were implanted but the level of expression was found to be decreased as time passed. Within the limitations of the present study, in this animal model, the transplantation of d-hMSCs enhanced the new bone formation around an implant and the survival and function of the stem cells was experimentally proven up to 12 weeks post-sacrifice.

In-situ stable injectable collagen-based hydrogels for cell and growth factor delivery.

Here we report development of in-situ stable injectable hydrogels for delivery of cells and growth factors based on two precursors, alginate, and collagen/calcium sulfate (CaSO4). The alg/col hydrogels were shear-thinning, injectable through commercially available needles and stable right after injection. Rheological measurements revealed that pre-crosslinked alg/col hydrogels fully crosslinked at 37°C and that the storage modulus of alg/col hydrogels increased with increasing the collagen content or the concentration of CaSO4. The viscoelastic characteristics and injectability of the alg/col hydrogels were not significantly impacted by the storage of precursor solutions for 28 days. An osteoinductive bone morphogenic protein-2 (BMP-2) loaded into alg/col hydrogels was released in 14 days. Human mesenchymal stem cells (hMSCs) encapsulated in alg/col hydrogels had over 90% viability over 7 days after injection. The DNA content of hMSC-laden alg/col hydrogels increased by 6-37 folds for 28 days, depending on the initial cell density. In addition, hMSCs encapsulated in alg/col hydrogels and incubated in osteogenic medium were osteogenically differentiated and formed a mineralized matrix. Finally, a BMP-2 loaded alg/col hydrogel was used to heal a critical size calvarial bone defect in rats after 8 weeks of injection. The alg/col hydrogel holds great promise in tissue engineering and bioprinting applications.

Visible Light-Enhanced Antibacterial and Osteogenic Functionality of Au and Pt Nanoparticles Deposited on TiO2 Nanotubes.

This study aimed at evaluating the visible light mediated antimicrobial and osteogenic applications of noble metal, such as gold (Au) and platinum (Pt) coated titania (TiO2) nanotubes (NTs). In this study, the Au and Pt nanoparticles (NPs) were deposited on anodized 100 nm TiO2 NTs by ion plasma sputtering. The Au and Pt NPs were mainly deposited on the top surface layer of TiO2 NTs and showed light absorbance peaks around the 470 and 600 nm visible light region used in this study, as seen from the surface characterization. From the results of antibacterial activity test, Au and Pt NPs that were deposited on TiO2 NTs showed excellent antibacterial activity under 470 nm visible light irradiation due to the plasmonic photocatalysis based on the localized surface plasmon resonance effect of the Au and Pt NPs. In addition, alkaline phosphate activity test and quantitative real-time PCR assay of osteogenic related genes resulted that these NPs promoted the osteogenic functionality of human mesenchymal stem cells (hMSCs) under 600 nm visible light irradiation, because of the synergic effect of the photothermal scattering of noble metal nanoparticles and visible light low-level laser therapy (LLLT). Therefore, the combination of noble metal coated TiO2 NTs and visible light irradiation would be expected to perform permanent antibacterial activity without the need of an antibacterial agent besides promoting osteogenic functionality.

Development of PLGA-PEG-COOH and gelatin-based microparticles dual delivery system and E-beam sterilization effects for controlled release of BMP-2 and IGF-1.

The purpose of this study was to develop a PLGA-PEG-COOH- and gelatin-based microparticles (MPs) dual delivery system for release of BMP-2 and IGF-1. We made and characterized the delivery system based on its morphology, loading capacity, Encapsulation efficiency and release kinetics. Second, we examined the effects of electron beam (EB) sterilization on BMP-2 and IGF-1 loaded MPs and their biological effects. Third, we evaluated the synergistic effect of a controlled dual release of BMP-2 and IGF-1 on osteogenesis of MSCs. Encapsulation efficiency of growth factors into gelatin and PLGA-PEG-COOH MPs are in the range of 64.78% to 76.11%. E-beam sterilized growth factor delivery systems were effective in significantly promoting osteogenesis of MSCs, although E-beam sterilization decreased the bioactivity of growth factors in MPs by approximately 22%. BMP-2 release behavior from gelatin MPs/PEG hydrogel shows a faster release (52.7%) than that of IGF-1 from the PLGA-PEG-COOH MPs/PEG hydrogel (27.3%). The results demonstrate that the gelatin and PLGA-PEG-COOH MPs based delivery system could realize temporal release of therapeutic biomolecules by incorporating different growth factors into distinct microparticles. EB sterilization was an accessible method for sterilizing growth factors loaded carriers, which could pave the way for implementing growth factor delivery in clinical applications.

Bone Regeneration Effect of Hyperbaric Oxygen Therapy Duration on Calvarial Defects in Irradiated Rats.

OBJECTIVE: In this study, we evaluated changes in bone remodeling in an irradiated rat calvarial defect model according to duration of hyperbaric oxygen therapy. MATERIALS AND METHODS: The 28 rats were divided into four groups. Radiation of 12 Gy was applied to the skull, and 5-mm critical size defects were formed on both sides of the skull. Bone grafts were applied to one side of formed defects. From the day after surgery, HBO was applied for 0, 1, and 3 weeks. At 6 weeks after bone graft, experimental sites were removed and analyzed for radiography, histology, and histomorphometry. RESULTS: Micro-CT analysis showed a significant increase in new bone volume in the HBO-3 group, with or without bone graft. When bone grafting was performed, BV, BS, and BS/TV all significantly increased. Histomorphometric analysis showed significant increases in %NBA and %BVN in the HBO-1 and HBO-3 groups, regardless of bone graft. CONCLUSION: Hyperbaric oxygen therapy was effective for bone regeneration with only 1 week of treatment.

The Impact of Metal Artifacts Within Cone Beam Computed Tomography Data on the Accuracy of Computer-Based Implant Surgery: An In Vitro Study.

PURPOSE: To evaluate differences in implant placement accuracy depending upon the presence or absence of metal restorations, as well as between distal extension and tooth-end cases. MATERIALS AND METHODS: Five experimental groups were designed with mandibular models exhibiting the following dental statuses: six anterior teeth and bilateral second molars, with bilaterally edentulous sites between them (group NN); six anterior teeth (group NDE); identical to group NN, with the six anterior teeth restored with metal crowns (group MN); identical to group NDE, with the six anterior teeth restored with metal crowns (group MDE); identical to group NN, with all remaining teeth restored with metal crowns (group MM). Six implants were placed on the bilateral first and second premolars and first molars; the linear and angular deviations between the preoperatively planned and actually placed implant positions were computed. RESULTS: Implant position errors were 0.55 to 0.87 mm and 0.53 to 0.80 mm at the entry point and apex, respectively, and were 0.35 to 0.71 mm and 2.02 to 3.12 degrees in depth and angular deviations, respectively. Significant differences were observed between groups NN and MM in overall deviations at the entry point (P = .009) and apex (P = .026), as well as in depth deviation (P = .008). CONCLUSION: The presence of metal restorations on all anterior and posterior remaining teeth resulted in significant differences in linear deviation at the entry point and apex between preoperatively planned and actually placed implant positions, compared with natural teeth without restorations. No significant differences were observed in placement accuracy between distal extension and tooth-end cases.

A prospective, split-mouth, clinical study of orthodontic titanium miniscrews with machined and acid-etched surfaces.

OBJECTIVES: To determine whether the success rate and primary stability of surface-treated miniscrews differ from those of nontreated miniscrews. MATERIALS AND METHODS: Patients who required one or more miniscrews for the same reason in each quadrant were recruited into a single-blinded, split-mouth, randomized, controlled trial with a 1:1 allocation ratio. Self-drilling miniscrews with two surface types were used: those with no surface treatment, and those with an acid-etched surface treatment. The cumulative success rate and primary stability of each type of miniscrew were examined, and factors potentially affecting the success and failure of miniscrews were investigated. RESULTS: Forty patients were included in the study, with a total of 98 orthodontic miniscrews. The overall success rate was 88.8%, and the respective success rates for acid-etched and machined surface miniscrews were 91.8% and 85.7%. The respective mean insertion torques were 13.62 ± 5.95 N·cm and 13.38 ± 4 N·cm, and periotest values measured immediately after insertion were -0.50 ± 2.77 for acid-etched miniscrews and -0.28 ± 3.36 for machined surface miniscrews. There was no significant difference in the mean insertion torques and periotest values according to surface treatment and jaw. CONCLUSIONS: Neither the success rate nor the primary stability of acid-etched surface miniscrews and machined surface miniscrews differed significantly. There is a high possibility that miniscrews will fall out in patients who have an open bite or those who require total distalization.