Exploring the impact of culture techniques and patient demographics on the success rate of primary culture of human periodontal ligament stem cells.

Background/purpose: Periodontal ligament stem cells (PDLSCs) have the potential for regenerating periodontal tissue. The study aims to investigate the impact of demographics (ages, gender, disease) and culture techniques (shipping storage time and culture method) on the success of primary culture. Materials and methods: PDLSCs were collected from 51 teeth of 26 patients and cultured via outgrowth (OG) and enzymatic digestion (ED) methods. Cells characteristics were confirmed by flow cytometry, MTT, and ARS. The primary culture success rate was evaluated with a serial chi-square test to determine the relationship with culture technique (ED/OG and ≤4 h/prolonged culture) and patient demographics (Young/Old, Female/Male, and Health/Periodontitis). Results: The overall success rate of Health group (69.7%) was higher than Periodontitis (38.9%). Culturing within 4 h possessed a higher success rate (71.8%) than prolonged group (16.7%) regardless of patient demographics, and using OG method (81.5%) revealed more promising. Subgroup analysis of 39 cases (culture within 4 h) found that the success rate of OG was higher than ED in the Old group (87.5%-25.0%) and in the Periodontitis group (83.3%-25.0%). Conclusion: Primary culturing of PDLSCs within 4 h and using the outgrowth method led to higher success rates regardless of patient demographics. It can achieve successful PDLSCs culture of older patients or patients with periodontal disease by appropriate culture technique.

Effects of an augmented reality aided system on the placement precision of orthodontic miniscrews: A pilot study.

Background/purpose: Augmented reality (AR) is gaining popularity in medical applications, which may aid clinicians in achieving improved clinical outcomes. The purpose of this study was to determine the positional and angle errors of orthodontic miniscrew placement by using a self-developed AR aided system. Materials and methods: Cone beam computed tomography (CBCT) and patient printed models were used in in vitro experiments. The participants were divided into a control group and an AR group, in which traditional orthodontic methods and the AR-aided system were used respectively. After the information obtained from the CBCT images and navigation system was combined on the display device, the AR-aided system indicated the planned miniscrew position to guide the clinicians during the placement of miniscrews. Both methods were compared by a senior and a junior dentist, and the position and angle of miniscrew placement were statistically analyzed using Wilcoxon's signed-rank and Mann-Whitney U tests. Results: When the AR-aided system was used, the accuracy of miniscrew placement in the mesiodistal position considerably increased (83%) when the procedure was performed by a senior clinician. In addition, the accuracy of miniscrew placement in the mesiodistal position and the angle of miniscrew placement considerably increased by approximately 67% and 72%, respectively, when the procedure was performed by a junior clinician. The position error of miniscrew placement was smaller for the junior clinician when the AR-aided system was used than for the senior clinician. Conclusion: The AR-aided system improved the accuracy of miniscrew placement regardless of the clinician's level of experience.

Association between the prognostic nutritional index (PNI) and all-cause mortality in patients with chronic kidney disease.

BACKGROUND: Nutrition and immunity play an important role in many chronic diseases. The prognostic nutritional index (PNI) has been proposed as a comprehensive indicator of an individual's immune and nutritional status. However, there is a lack of evidence regarding the association between the PNI and mortality in patients with chronic kidney disease (CKD). METHODS: We used National Health and Nutrition Examination Survey (NHANES) data from 2001-2014 for participants with CKD. Mortality data were obtained from the National Death Index and matched to NHANES participants. Cox proportional hazards models were used to estimate hazard ratios for all-cause mortality.Results: The patients were 72.5 ± 9.8 years old, and 47.57% were male. The median follow-up was 58 months, and the mortality rate in patients with CKD was 30.27%. A higher PNI protected against all-cause mortality in patients with CKD, with an adjusted hazard ratio (aHR) of 0.98 (95% confidence interval (CI): 0.97-0.99). After grouping according to PNI quartiles, statistically significant between-group differences were observed in survival probabilities. The aHR for the lowest PNI quartile compared to the highest PNI quartile was 1.64 (95% CI: 1.26-2.14). Sensitivity analysis further supported this association. Restricted cubic spline analysis revealed an L-shaped association between the PNI and all-cause mortality in patients with CKD, with a critical value of 50.5. CONCLUSIONS: The PNI is a protective factor in patients with CKD, with an L-shaped decrease in all-cause mortality with an increasing PNI.

Improved super-elastic Ti-Ni alloy wire for treating adult skeletal class III with facial asymmetry: A case report.

BACKGROUND: Correcting severe skeletal class III malocclusion with facial asymmetry in adults through orthodontic treatment alone is difficult. CASE SUMMARY: In this case report, we describe orthodontic treatment and lower incisor extraction without orthognathic surgery for a 27-year-old man with a transverse discrepancy. The extraction sites were closed using an elastic chain. The use of intermaxillary elastics, improved super-elastic Ti-Ni alloy wire, and unilateral multibend edgewise arch wire was crucial for correcting facial asymmetry and the midline deviation. CONCLUSION: After treatment, the patient had a more symmetrical facial appearance, acceptable overjet and overbite, and midline coincidence. The treatment results remained stable 3 years after treatment. This case report demonstrates that a minimally invasive treatment can successfully correct severe skeletal class III malocclusion with facial asymmetry.

Improved super-elastic Ti-Ni alloy wire intrusion arch for skeletal class II malocclusion combined with deep overbite: A case report.

BACKGROUND: Treatment for deep overbite cases can be difficult. This case report presents some techniques with improved super-elastic Ti-Ni alloy wire (ISW) for deep overbite correction. CASE SUMMARY: A 21-year-old woman had a chief complaint of flaring maxillary teeth. Orthodontic evaluation revealed a skeletal class II malocclusion and a convex profile appearance. A deep overbite with palatal impingement and large overjet were also noted. Bilateral maxillary first premolars were extracted, and spaces were closed using a closed-coil spring and elastic chain. The deep overbite was corrected by applying the ISW curve and ISW intrusion arch. Intermaxillary elastics was used to adjust the intermaxillary relationship. Active treatment took approximately 3 years, and the appearance and dentition alignment noticeably improved. CONCLUSION: The use of the ISW technique in a case of skeletal class II malocclusion with deep overbite achieved a desirable result, and the patient was satisfied with the treatment outcome.

Effect of Various Airborne Particle Abrasion Conditions on Bonding between Polyether-Ether-Ketone (PEEK) and Dental Resin Cement.

The effects of alumina particle size and jet pressure on the bond strength of polyetheretherketone (PEEK) were examined to determine the airborne particle abrasion parameters with minimal effects on PEEK and to achieve optimal bond strength, as a reference for future clinical use. An alumina particle with four particle sizes and three jet pressures was used to air-abrade PEEK. Surface roughness (Ra), morphology, chemical structure, and wettability were analyzed using a stylus profilometer, scanning electron microscope, X-ray diffractometer, and contact angle analyzer, respectively. The shear bond strength (SBS) of PEEK and dental resin cement was analyzed using a universal testing machine (n = 10). The failure modes and debonded fracture surfaces were observed using optical microscopy. Airborne particle abrasion increased the Ra and hydrophobicity of PEEK and deposited alumina residues. The SBS generally decreased after thermal cycling. A large particle size damaged the PEEK surface. The effects of different particle sizes and jet pressures on the SBS were only significant in certain groups. Adhesive failure was the main mode for all groups. Within the limitations of this study, 110 µm grain-sized alumina particles combined with a jet pressure of 2 bar prevented damage to PEEK, providing sufficient SBS and bonding durability between PEEK and dental resin cement.

Risk factors for hospital readmissions in pneumonia patients: A systematic review and meta-analysis.

BACKGROUND: Factors that are associated with the short-term rehospitalization have been investigated previously in numerous studies. However, the majority of these studies have not produced any conclusive results because of their smaller sample sizes, differences in the definition of pneumonia, joint pooling of the in-hospital and post-discharge deaths and lower generalizability. AIM: To estimate the effect of various risk factors on the rate of hospital readmissions in patients with pneumonia. METHODS: Systematic search was conducted in PubMed Central, EMBASE, MEDLINE, Cochrane library, ScienceDirect and Google Scholar databases and search engines from inception until July 2021. We used the Newcastle Ottawa (NO) scale to assess the quality of published studies. A meta-analysis was carried out with random-effects model and reported pooled odds ratio (OR) with 95% confidence interval (CI). RESULTS: In total, 17 studies with over 3 million participants were included. Majority of the studies had good to satisfactory quality as per NO scale. Male gender (pooled OR = 1.22; 95%CI: 1.16-1.27), cancer (pooled OR = 1.94; 95%CI: 1.61-2.34), heart failure (pooled OR = 1.28; 95%CI: 1.20-1.37), chronic respiratory disease (pooled OR = 1.37; 95%CI: 1.19-1.58), chronic kidney disease (pooled OR = 1.38; 95%CI: 1.23-1.54) and diabetes mellitus (pooled OR = 1.18; 95%CI: 1.08-1.28) had statistically significant association with the hospital readmission rate among pneumonia patients. Sensitivity analysis showed that there was no significant variation in the magnitude or direction of outcome, indicating lack of influence of a single study on the overall pooled estimate. CONCLUSION: Male gender and specific chronic comorbid conditions were found to be significant risk factors for hospital readmission among pneumonia patients. These results may allow clinicians and policymakers to develop better intervention strategies for the patients.

Evaluating the Effect of Different Polymer and Composite Abutments on the Color Accuracy of Multilayer Pre-Colored Zirconia Polycrystal Dental Prosthesis.

With increasing aesthetic awareness and emphasis on time costs in today's society, monolithic multilayer precolored zirconia ceramics (M-Zr) facilitate aesthetic restorations in a convenient and straightforward manner without the need for veneering porcelain to modify the color. However, the effect of abutment materials on the final color of M-Zr remains unclear. Herein, we placed Vita A1 Shade M-Zr on six different abutment materials, zirconia (Y-TZP), 3D printed composite resin (CR), dental model resin (MR), polyetheretherketone (PEEK), polyetherketoneketone (PEKK), and cobalt−chromium alloy (Co−Cr), to evaluate their effect on the color accuracy of M-Zr. The color attributes (L*, a*, and b*) were measured using a dental spectrophotometer. The translucency parameter (TP), contrast ratio, color difference (ΔE) between each background substrate and the Vita A1 Shade Guide, and chroma values (C) were calculated to evaluate the color accuracy of M-Zr. A statistical analysis was performed using one-way analysis of variance and post hoc Tukey's HSD tests (α = 0.05). The experimental results indicate that the TP values and contrast ratio of the M-Zr samples were 14.85 and 0.83, respectively. Co−Cr had the highest ΔE (6.08) and lowest C value (7.52); PEKK had the lowest ΔE (2.60), and PEEK had the highest C value (12.23) (p < 0.05). Notably, the ΔE values of CR (3.13), PEEK (2.86), and PEKK were within clinical indicators (ΔE < 3.7). Based on these results, it can be concluded that the abutment material has a significant effect on the final color of the M-Zr, and PEEK or PEKK resulted in good color accuracy. When choosing the dental MR, traditional zirconia, or metals as abutment materials, colored or opaque cement might be required to eliminate color distortion and achieve desirable optical properties.

Potent Anti-SARS-CoV-2 Efficacy of COVID-19 Hyperimmune Globulin from Vaccine-Immunized Plasma.

Coronavirus disease 2019 (COVID-19) remains a global public health threat. Hence, more effective and specific antivirals are urgently needed. Here, COVID-19 hyperimmune globulin (COVID-HIG), a passive immunotherapy, is prepared from the plasma of healthy donors vaccinated with BBIBP-CorV (Sinopharm COVID-19 vaccine). COVID-HIG shows high-affinity binding to severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike (S) protein, the receptor-binding domain (RBD), the N-terminal domain of the S protein, and the nucleocapsid protein; and blocks RBD binding to human angiotensin-converting enzyme 2 (hACE2). Pseudotyped and authentic virus-based assays show that COVID-HIG displays broad-spectrum neutralization effects on a wide variety of SARS-CoV-2 variants, including D614G, Alpha (B.1.1.7), Beta (B.1.351), Gamma (P.1), Kappa (B.1.617.1), Delta (B.1.617.2), and Omicron (B.1.1.529) in vitro. However, a significant reduction in the neutralization titer is detected against Beta, Delta, and Omicron variants. Additionally, assessments of the prophylactic and treatment efficacy of COVID-HIG in an Adv5-hACE2-transduced IFNAR-/- mouse model of SARS-CoV-2 infection show significantly reduced weight loss, lung viral loads, and lung pathological injury. Moreover, COVID-HIG exhibits neutralization potency similar to that of anti-SARS-CoV-2 hyperimmune globulin from pooled convalescent plasma. Overall, the results demonstrate the potential of COVID-HIG against SARS-CoV-2 infection and provide reference for subsequent clinical trials.

Bone quality affects stability of orthodontic miniscrews.

The objective of this study was to evaluate the effect of bone-miniscrew contact percentage (BMC%) and bone quality and quantity on orthodontic miniscrew stability and the maximum insertion torque value (ITV). Orthodontic miniscrews of five different dimensions and several bovine iliac bone specimens were used in the evaluation. Miniscrews of each dimension group were inserted into 20 positions in bovine iliac bone specimens. The experiment was divided into three parts: (1) Bone quality and quantity were evaluated using cone-beam computed tomography (CBCT) and microcomputed tomography. (2) The 3D BMC% was calculated. (3) The ITVs during miniscrew insertion were recorded to evaluate the stability of the orthodontic miniscrews. The results indicated that longer and thicker miniscrews enabled higher ITVs. CBCT was used to accurately measure cortical bone thickness (r = 0.939, P < 0.05) and to predict the bone volume fraction of cancellous bone (r = 0.752, P < 0.05). BMC% was significantly influenced by miniscrew length. The contribution of cortical bone thickness to the ITV is greater than that of cancellous bone structure, and the contribution of cortical bone thickness to BMC% is greater than that of cancellous bone structure. Finally, the higher is BMC%, the greater is the ITV. This study concludes that use of CBCT may predict the mechanical stability of orthodontic miniscrews.

[Seminal vesiculoscopy: Safe and effective for the treatment of refractory hemospermia].

OBJECTIVE: To investigate the clinical effect and safety of transutricular seminal vesiculoscopy in the treatment of refractory hemospermia. METHODS: Using 6Fr ureteroscopy through the prostatic utricle, we treated 103 cases of refractory hemospermia with distal seminal duct obstructive lesions, including 12 cases complicated by distal seminal duct cyst. We rinsed the seminal duct cavity, cleaned out the stones, removed the cyst wall with holmium laser and followed up the patients for 12 months postoperatively. RESULTS: The operations were successfully completed in all the cases but 1 (0.9%), in which the ureteroscope failed to enter the bilateral seminal vesicles. The operation time was (47 ± 9) min. No rectal injury or acute epididymitis occurred intraoperatively, nor fever, long-term dysuria or long-term hematuria after surgery. Postoperative follow-up showed that bloody semen symptoms vanished in 93 (90.3%) of the cases, improved significantly in 4 (3.9%) and not significantly in 2 (1.9%), and 3 cases of recurrence (2.9%) were all relieved after reoperation. CONCLUSION: Transutricular seminal vesiculoscopy has the advantages of clear anatomic vision, minor invasiveness and significant effectiveness in the treatment of refractory hemospermia. What's more, holmium laser is better than plasmakinetic resection in removal of the cyst wall.

Biomechanical Effect of Orthodontic Treatment of Canine Retraction by Using Metallic Orthodontic Mini-Implant (OMI) Covered with Various Angles of Revolving Cap.

OBJECTIVE: This study evaluated the biomechanical effects of a metallic orthodontic mini-implant (OMI) covered with various types of angled revolving cap on the peri-OMI bone and the canine periodontal ligament (PDL) by finite element (FE) analyses. MATERIALS AND METHODS: Three-dimensional FE models included comprised cortical bone and cancellous bone of the maxilla, and the OMIs were created. The forces (0.98 N) pulled in both the canine hook and the revolving cap, pulling towards each other in both directions as loading conditions. The upper surface of the maxilla was fixed as a boundary condition. RESULTS: The bone stresses were increasing in the models by using OMI covered with a revolving cap as compared with that in the conventional model (in which only the OMI was placed). However, no obvious differences in bone stresses were observed among the models with various types of angled revolving cap. The minimum principal strain in the canine PDL was highest for condition 180T, followed by condition 180L. However, the maximum differences in the values between each experimental model and the conventional model were around 5%. CONCLUSION: This study showed no obvious effects in decreasing or increasing stress/strain in bone and PDL by using various types of angled revolving cap covered metallic mini-implant in orthodontic treatment of canine retraction.

Comparison of neoadjuvant chemotherapy followed by surgery vs. surgery alone for locally advanced gastric cancer: a meta-analysis.

BACKGROUND: The neoadjuvant chemotherapy is increasingly used in advanced gastric cancer, but the effects on safety and survival are still controversial. The objective of this meta-analysis was to compare the overall survival and short-term surgical outcomes between neoadjuvant chemotherapy followed by surgery (NACS) and surgery alone (SA) for locally advanced gastric cancer. METHODS: Databases (PubMed, Embase, Web of Science, Cochrane Library, and Google Scholar) were explored for relative studies from January 2000 to January 2021. The quality of randomized controlled trials and cohort studies was evaluated using the modified Jadad scoring system and the Newcastle-Ottawa scale, respectively. The Review Manager software (version 5.3) was used to perform this meta-analysis. The overall survival was evaluated as the primary outcome, while perioperative indicators and post-operative complications were evaluated as the secondary outcomes. RESULTS: Twenty studies, including 1420 NACS cases and 1942 SA cases, were enrolled. The results showed that there were no significant differences in overall survival (P = 0.240), harvested lymph nodes (P = 0.200), total complications (P = 0.080), and 30-day post-operative mortality (P = 0.490) between the NACS and SA groups. However, the NACS group was associated with a longer operation time (P < 0.0001), a higher R0 resection rate (P = 0.003), less reoperation (P = 0.030), and less anastomotic leakage (P = 0.007) compared with SA group. CONCLUSIONS: Compared with SA, NACS was considered safe and feasible for improved R0 resection rate as well as decreased reoperation and anastomotic leakage. While unbenefited overall survival indicated a less important effect of NACS on long-term oncological outcomes.

Shear Bonding Strength and Thermal Cycling Effect of Fluoride Releasable/Rechargeable Orthodontic Adhesive Resins Containing LiAl-F Layered Double Hydroxide (LDH) Filler.

This study aims to investigate the shear bonding strength (SBS) and thermal cycling effect of orthodontic brackets bonded with fluoride release/rechargeable LiAl-F layered double hydroxide (LDH-F) contained dental orthodontic resin. 3% and 5% of LDH-F nanopowder were gently mixed to commercial resin-based adhesives Orthomite LC (LC, LC3, LC5) and Transbond XT (XT, XT3). A fluoroaluminosilicate modified resin adhesive Transbond color change (TC) was selected as a positive control. Fifteen brackets each group were bonded to bovine enamel and the SBS was tested with/without thermal cycling. The adhesive remnant index (ARI) was evaluated at 20× magnification. The fluoride-releasing/rechargeability and cytocompatibility were also evaluated. The SBS of LC, LC3, and LC5 were significantly higher than XT and TC. After thermal cycling, the SBS of LC, LC3, and LC5 did not decrease and was significantly higher than TC. The changes of ARI scores indicate that failure occurred not only cohesive but also semi-cohesive fracture. The 30 days accumulated daily fluoride release of LC3, LC5, and TC without recharge are higher than 300 µg/cm2. The LDH-F contained resin adhesive possesses higher SBS compared to positive control TC. Fluoride release and the rechargeable feature can be achieved for preventing enamel demineralization without cytotoxicity.

Effects of short-term acupuncture treatment on occlusal force and mandibular movement in patients with deep-bite malocclusion.

BACKGROUND/PURPOSE: Acupuncture is well known to be effective for pain relief and muscle relaxation, and hence it is feasible that acupuncture treatment could change the occlusal forces and mandibular movements in subjects with deep-bite malocclusion. The purpose of this research was to determine the distribution of occlusal force and the border movement of the mandible in patients with deep-bite malocclusion before and after acupuncture treatment. MATERIALS AND METHODS: This study involved 17 volunteers with deep-bite malocclusion and aged 20-30 years. Before and after acupuncture treatment, the distribution of the occlusal-force percentage at each tooth was measured and the percentage biting force in the first molar area during maximal clenching was recorded. Additionally, the mandibular movements including the maximum mouth opening and maximum lateral border movement were also evaluated. All of the data were analyzed statistically using the Wilcoxon signed-rank test. RESULTS: The percentage biting force at the first molar differed significantly between before and after the acupuncture treatments (P = 0.017). However, no treatment effects were seen for the maximum mouth opening and the maximum lateral border movement. Conclusion: Although the mandibular border movements did not change significantly, this study has confirmed that acupuncture treatment may become an alternative choice on improving the occlusal force of deep-bite patients.

Customized surgical template fabrication under biomechanical consideration by integrating CBCT image, CAD system and finite element analysis.

This study developed a customized surgical template under mechanical consideration for molar intrusion. Two finite element (FE) models were analyzed for the primary stability under 100 gf traction forces with one mini-screw inserted at the buccal side in horizontal and another in palatal side with two optional positions at 60° (P60) or 15° (P15) angles with inclination toward the molar occlusal surface. The surgical template was generated using rapid prototyping (RP) printing for the clinical application based on improved primarily stability model. The surrounding bone strains for models P15 and P60 were far lower than the bone remodeling critical value. Model P60 presented much lower micro-motion in the screw/bone interface and the screw head displacement than those values in model P15. Using FE analysis for biomechanical evaluation and combining with CT image, image superimposed method and CAD technique can fabricate accuracy/security customized surgical template for mini-screws with better primary stability.

Developing Customized Dental Miniscrew Surgical Template from Thermoplastic Polymer Material Using Image Superimposition, CAD System, and 3D Printing.

This study integrates cone-beam computed tomography (CBCT)/laser scan image superposition, computer-aided design (CAD), and 3D printing (3DP) to develop a technology for producing customized dental (orthodontic) miniscrew surgical templates using polymer material. Maxillary bone solid models with the bone and teeth reconstructed using CBCT images and teeth and mucosa outer profile acquired using laser scanning were superimposed to allow miniscrew visual insertion planning and permit surgical template fabrication. The customized surgical template CAD model was fabricated offset based on the teeth/mucosa/bracket contour profiles in the superimposition model and exported to duplicate the plastic template using the 3DP technique and polymer material. An anterior retraction and intrusion clinical test for the maxillary canines/incisors showed that two miniscrews were placed safely and did not produce inflammation or other discomfort symptoms one week after surgery. The fitness between the mucosa and template indicated that the average gap sizes were found smaller than 0.5 mm and confirmed that the surgical template presented good holding power and well-fitting adaption. This study addressed integrating CBCT and laser scan image superposition; CAD and 3DP techniques can be applied to fabricate an accurate customized surgical template for dental orthodontic miniscrews.

Changes in mandibular border movements in adult patients after correction of functional anterior crossbite.

BACKGROUND/PURPOSE: An effective approach for assessing masticatory function is necessary. The goal of this study was to establish an efficient method for evaluating mandibular border movements in patients after functional anterior crossbite was corrected. MATERIALS AND METHODS: Five patients with functional anterior crossbite were included in this study. They were treated with edgewise appliance and improved super-elastic nickel-titanium archwire. The digital images were collected before and after anterior crossbite was corrected. The trajectory paths of mandibular border movement were evaluated on both the frontal and sagittal planes. RESULTS: When the mandibular border movement paths were analyzed on the frontal plane for the vertical displacement, significant increases in the maximum left- and right-lateral movements were observed. For the horizontal displacement, although decreasing trends were observed in the maximum mouth opening and protrusive movements, no significant difference was detected. However, horizontal displacements were generally greater in men than in women. When the mandibular border movement paths were analyzed on the sagittal plane, significant increases in all the vertical and horizontal displacements were observed at all border movements, except the maximum mouth opening. However, if the data were compared between men and women, significant difference was shown only in the horizontal displacement of the maximum protrusion. CONCLUSION: On both the frontal and sagittal planes, after correction of the anterior crossbite there are increases in vertical and horizontal displacements at all kinds of mandibular border movements except for the horizontal displacements at the maximum mouth opening and the maximum protrusion.

Does Orthodontic Treatment Affect the Alveolar Bone Density?

Few studies involving human participants have been conducted to investigate the effect of orthodontic treatment on alveolar bone density around the teeth. Our previous study revealed that patients who received 6 months of active orthodontic treatment exhibited an ∼24% decrease in alveolar bone density around the teeth. However, after an extensive retention period following orthodontic treatment, whether the bone density around the teeth can recover to its original state from before the treatment remains unclear, thus warranting further investigation.The purpose of this study was to assess the bone density changes around the teeth before, during, and after orthodontic treatment.Dental cone-beam computed tomography (CBCT) was used to measure the changes in bone density around 6 teeth in the anterior maxilla (maxilla central incisors, lateral incisors, and canines) of 8 patients before and after orthodontic treatment. Each patient underwent 3 dental CBCT scans: before treatment (T0); at the end of 7 months of active orthodontic treatment (T1); after several months (20-22 months) of retention (T2). The Friedman test was applied to evaluate the changes in the alveolar bone density around the teeth according to the 3 dental CBCT scans.From T0 to T1, a significant reduction in bone density was observed around the teeth (23.36 ±â€Š10.33%); by contrast, a significant increase was observed from T1 to T2 (31.81 ±â€Š23.80%). From the perspective of the overall orthodontic treatment, comparing the T0 and T2 scans revealed that the bone density around the teeth was relatively constant (a reduction of only 0.75 ±â€Š19.85%). The results of the statistical test also confirmed that the difference in bone density between T0 and T2 was nonsignificant.During orthodontic tooth movement, the alveolar bone density around the teeth was reduced. However, after a period of bone recovery, the reduced bone density recovered to its previous state from before the orthodontic treatment. However, the bone density around ∼10% of the teeth in this region could not recover to 80% of its state from before the orthodontic treatment.

A Revolving Temporary Anchorage Cap Connecting to an Orthodontic Miniscrew Using In Vitro Experimental Testing: Safety and Biomechanical Evaluations.

PURPOSE: This study is to develop a plastic revolving (translation and rotation) temporary anchorage cap (TAC) as the orthodontic anchor and evaluate its biomechanical safety and clinical used feasibility. MATERIALS AND METHODS: The TAC was designed to connect onto a mini-implant head with 45-degree switching unit and extended arm for tying an orthodontic elastic chain/coil spring. The removal force between the TAC and mini-implant head and torque resistance on the mini-implant/bone interface were performed to evaluate the biomechanical safety. Clinical molar uprighting and mesial drive application were performed to reveal the TAC feasibility/capacity. RESULTS: The removal force was 43.95 N (>>finger-pulling force 9.3 N) to prevent the TAC from detaching, and the torque resistance was 159.25 N·mm to maintain micromotion smaller than 30.4 µm between the screw and bone. The strain value in using TAC treatment was found to be about 2 times that of traditional tracing (without using TAC) in molar uprighting/mesial drive application. CONCLUSIONS: The plastic revolving TAC can provide optional use with translation/rotation features to change the angles and directions in orthodontic tractions and increase treatment efficiency under biomechanical safety considerations.