Color changes of nanocomposites used for clear aligner attachments: an in vitro study.

PURPOSE: The purpose of this study was to compare the color changes of two different nanocomposites used for two different designs of clear aligner attachments. METHODS: In all, 120 human premolars were embedded in 12 upper dental models with 10 premolars in each model. Models were scanned and attachments were digitally designed. Conventional attachments (CA) were prepared for the first six models and optimized multiplane attachments (OA) were prepared for the other six models with packable composite (PC) on the right quadrant and flowable composite (FC) on the left quadrant of each model. The models were subjected to 2000 thermal cycles at 5 °C/55 °C and then consecutively immersed in the five different staining solutions each for 48 h to simulate external discoloration. Color measurements were taken with a spectrophotometer. Color changes (∆E*ab) of the attachments before and after immersion were compared with the Commission Internationale de l'Éclairage L*a*b* (CIELAB) color space approach. RESULTS: When ∆E*ab values were examined, no significant difference was observed between the groups according to the attachment type (P > 0.05). After the coloration process, the flowable composite group showed less coloration than the packable composite group for both attachment designs (P < 0.05). Color difference values after the staining procedure were significantly higher in the CA-PC and OA-PC groups compared to the CA-FC and OA-FC groups (P < 0.05). CONCLUSION: Color change of the packable nanocomposite was more pronounced than that of the flowable nanocomposite for both attachment designs. Therefore, clear aligner attachments created using flowable nanocomposite can be recommended, especially in the anterior region where esthetics are important for the patient.

A new patient-specific overformed anatomical implant design method to reconstruct dysplastic femur trochlea.

Patellar luxation with condylar defect is a challenging situation for reconstruction in humans. Patella reluxation, cartilage damage and pain are the most common complications. This study aims to present a new patient specific method of overformed implant design and clinical implantation that prevents luxation of patella without damaging the cartilage in a dog. Design processes are Computer Tomography, Computer Assisted Design, rapid prototyping of the bone replica, creation of the implant with surgeon's haptic knowledge on the bone replica, 3D printing of the implant and clinical application. The implant was fully seated on the bone. Patella reluxation or implant-related bone problem was not observed 80 days after the operation. However, before the implant application, there were soft tissue problems due to previous surgeries. Three-point bending test and finite element analysis were performed to determine the biomechanical safety of the implant. The stress acting on the implant was below the biomechanical limits of the implant. More cases with long-term follow-up are needed to confirm the success of this method in patellar luxation. Compared with trochlear sulcoplasty and total knee replacement, there was no cartilage damage done by surgeons with this method, and the implant keeps the patella functionally in sulcus. This is a promising multidisciplinary method that can be applied to any part of the bone and can solve some orthopaedic problems with surgeon's haptic knowledge.

Emergence of West Nile Virus Lineage-2 in Resident Corvids in Istanbul, Turkey.

West Nile fever is a vector-borne viral disease affecting animals and humans causing significant health and economic problems globally. This study was aimed at investigating circulating West Nile virus (WNV) strains in free-ranging corvids in Istanbul, Turkey. Brain, liver, and kidney were collected from corvids (n = 34) between June 2019 and April 2020 and analyzed for the presence of WNV-specific RNA by quantitative RT-PCR. In addition, histopathologic and immunohistochemical examinations were also performed. Samples found to be positive by qRT-PCR were partially sequenced. WNV-specific RNA was detected in 8 of 34 corvids analyzed, which included 7 hooded crows (Corvus cornix) and 1 Eurasian magpie (Pica pica). Phylogenetic analysis based on partial WNV sequences from the 8 WNV-positive corvids identified in this study revealed that all sequences clustered within the WNV lineage-2; they were at least 97% homologues to WNV lineage-2 sequences from Slovakia, Italy, Czechia, Hungary, Senegal, Austria, Serbia, Greece, Bulgaria, and Germany. WNV sequences showed a divergence (87.94-94.46%) from sequences reported from Romania, Central African Republic, South Africa, Madagascar, Israel, and Cyprus, which clustered into a different clade of WNV lineage-2. Common histopathologic findings of WNV-positive corvids included lymphoplasmacytic hepatitis, myocarditis, and splenitis. The liver and heart were found to be the tissues most consistently positive for WNV-specific antigen by immunohistochemistry, followed by the kidney and brain. This study demonstrates for the first time the existence of WNV virus belonging to the genetic lineage-2 in resident corvids in Istanbul, Turkey. We hypothesize that the WNV strains circulating in Istanbul are possibly the result of a spillover event from Europe. Since WNV is a zoonotic pathogen transmitted by mosquito vectors, the emergence of WNV in Istanbul also poses a risk to humans and other susceptible animals in this densely populated city and needs to be addressed by animal and public health authorities.

Treatment of fractures and other orthopedic problems in cats and dogs using versatile external fixator / Tratamento de fraturas de extremidades de cães e gatos usando fixador externo versátil

Many complicated bone fractures can be healed by different techniques including linear external fixation. New generation linear external fixators enhanced the scope of application for bone fractures by mechanical progress. Difficulties include implementing enough pins through fixation clamps to the comminuted fragments or clamp addition and fixing it properly to the rod with the correct pin insertion angle. Effective configurations may not always result. This study sought to reveal the clinical efficiency of modified clamps of a versatile external fixator (VEF) to fix different types of fractures and orthopedic problems according to the radiographic and clinical results. We used this fixator on 17 cats and 17 dogs of different ages and sizes, having different types of antebrachium, humerus, tibia, ulna fractures, and bone-muscle deformities. Clamps had different features to connect fixator pins. Many fixator configurations were created according to the fracture type and body weight of the animals. The most used ones were unilateral and bilateral configurations. The callus formation and visual gait analysis were observed after the operations, until the removal of the fixator. After fixator removal, the visual gait status of the limbs was excellent in 67% of the cases, good in 15%, fair in 12%, and poor in 6%. We found that rods and fixator pins were connected easily by semi-locked clamps. Also, the double pin holding clamps saved space on the fixation rod by the application of two pins through one clamp. We think that clamps of versatile external fixators can easily be constructed to limb fractures and save time during surgery.(AU)

Diversas fraturas ósseas complicadas podem ser tratadas por diferentes técnicas, incluindo fixadores externos lineares. Os fixadores externos lineares de nova geração aumentaram o escopo de aplicação para fraturas ósseas devido ao progresso mecânico. A dificuldade é implementar um número suficiente de pinos através de clamps de fixação aos fragmentos osseos ou adição de clamps com fixação adequadamente à haste com o ângulo correto de inserção do pino. As configurações eficazes nem sempre podem ser realizadas. Este estudo pretendia revelar a eficácia clínica das clamps modificadas de um fixador externo versátil para corrigir diferentes tipos de fraturas e problemas ortopédicos de acordo com os resultados radiográficos e clínicos. O fixador foi utilizado em 17 gatos e 17 cães de diferentes idades e tamanhos, com diferentes tipos de antebraço, úmero, tíbia, fratura de ulna e deformidades ósseo-musculares. Os clamps tinham recursos diferentes para conectar os pinos do fixador. Muitas configurações de fixadores foram criadas de acordo com o tipo de fratura e peso corporal dos animais. As mais utilizadas foram as configurações unilateral e bilateral. A formação do calo e a análise visual da marcha foram observadas após as cirurgias, até a retirada do fixador. Após a retirada do fixador, a utilização dos membros foi excelente em 67% dos casos, bom em 15% dos casos, regular em 12% dos casos, ruim em 6% dos casos. Concluímos que as hastes e os pinos do fixador foram facilmente conectados por clamps semi-travados. Além disso, os clamps de fixação de pino duplo economizaram espaço na haste de fixação com a aplicação de dois pinos em clamp. Acreditamos que os clamps de fixadores externos versáteis podem ser facilmente construídas para fraturas de membros, economizando tempo na cirurgia.(AU)

Identification of Newcastle disease virus subgenotype VII.2 in wild birds in Turkey.

BACKGROUND: Newcastle disease viruses (NDVs) can spread across continents via migratory birds. Hence, we investigated the frequency of NDV in both non-migratory and birds migrating on the Black Sea-Mediterranean flyway, in Istanbul, Turkey. Birds were trapped using nets placed around the Kucukcekmece lake Avcilar, Istanbul, in spring seasons of 2016 and 2018. In total, 297 birds belonging to 42 different species were trapped, categorized according to species and sex, and flocked oropharyngeal swabs were collected. In addition, flocked swabs were also collected from 115 mallards caught by hunters around Edirne and from 207 birds which had been treated in the Veterinary Faculty of Istanbul university-Cerrahpasa. Tissue samples were taken from dead wild birds brought by public to Veterinary Faculty. A total of 619 flocked oropharyngeal swabs were pooled into 206 samples. RNA was extracted from swabs and tissue samples. Real-time RT-PCR prob. assay was used to detect NDV-RNA in samples. RESULTS: There was no amplification in real time RT-PCR in samples taken from wild birds caught by traps. However, amplification of NDV-F gene was observed in oropharyngeal swabs taken from 2 waterfowls (Common Moorhen and Mallard), and in tissue samples taken from 2 little owls and 1 common kestrel. Sequencing and phylogenetic analyses of these 5 samples for NDV-F gene showed great similarity with NDV subgenotype VII.2 viruses. Analysis also showed that there is a high similarity with the F gene sequences previously reported from Turkey in 2012 and as well as the sequences from neighbouring countries Bulgaria and Georgia and geographically close country such as Pakistan. Although the strains found in this study are closely related, there is a relatively small degree of molecular divergence within 543 bp of F gene of the Turkish NDV isolate and strains detected in Israel, Pakistan, Iran, United Arab Emirates and Belgium. CONCLUSIONS: Our findings revealed the presence of subgenotype VII.2 of NDVs in wild birds in north west of Turkey and demonstrated some degree of molecular evolution when compared to the earlier NDV-VII.2 isolate in Turkey.

Repair of Tibiotarsal Rotation in 7 Chukar Partridges (Alectoris chukar) and 12 Domestic Pigeons (Columba livia domestica) with Type-2 External Skeletal Fixator Intramedullary Pin Tie-in.

Rotational deformities of the long bones affect various avian species. Tibiotarsal rotation may cause the leg to deviate up to 180° from the dorsoplantar axis in a matter of days, thus preventing the birds from walking freely and leading to the inability to stand. In this study, tibiotarsal rotation observed in pigeons and partridges was managed by creating a closed fracture in the tibiotarsus and then, following reduction, stabilizing it with an intramedullary tie-in Type 2 external skeletal fixation system. Functional healing was achieved in 12 pigeons (Columba livia domestica; mean healing time, 38 days) and 7 partridges (Alectoris chukar; mean healing time, 40 days). This treatment was successful. In small bird species (<1 kg), this simple and inexpensive surgical intervention may provide a highly effective method for the treatment of rotational deformities.

Effects of a fluoride-containing casein phosphopeptide-amorphous calcium phosphate complex on the shear bond strength of orthodontic brackets.

The purpose of this study was to investigate the effects of enamel pre-treatment with a new fluoride-containing casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) complex on the shear bond strength (SBS) of brackets bonded with etch-and-rinse or self-etching adhesive systems. The material comprised 66 extracted human premolars randomly divided into six equal groups with respect to the enamel pre-treatment and adhesive system employed: 1. No pre-treatment and brackets bonded with the etch-and-rinse adhesive system (Transbond XT). 2. Pre-treatment with fluoride-containing CPP-ACP paste (MI Paste Plus) and Transbond XT. 3. Pre-treatment with non-fluoride CPP-ACP paste (MI Paste) and Transbond XT.4. No pre-treatment and brackets bonded with the self-etching adhesive system (Transbond Plus). 5 and 6. Enamel pre-treated as for groups 2 and 3, respectively, and the Transbond Plus. Bonded specimens were subjected to thermal cycling (×1000) before SBS testing. The residual adhesive on the enamel surface was evaluated after debonding with the adhesive remnant index (ARI). Data evaluation was made using one-way analysis of variance and Tukey test for SBS results, and Kruskal-Wallis test for ARI results. The results showed that enamel pre-treatment with either fluoride or non-fluoride CPP-ACP paste had no significant effect on the SBS of the self-etching adhesive system (P > 0.05). Enamel pre-treatment with non-fluoride CPP-ACP in group 3 significantly reduced the SBS of the etch-and-rinse adhesive (P < 0.001), while pre-treatment with fluoride-containing CPP-ACP paste (groups 2 and 5) did not affect debonding values (P > 0.05). The fluoride-containing CPP-ACP did not compromise the SBS of brackets bonded with the tested etch-and-rinse and self-etching systems, but its non-fluoride version significantly decreased the SBS of the etch-and-rinse adhesive system.

[Evaluation of soft tissue reactions to three nonabsorbable suture materials in a rabbit model]. / Uç degisik emilmeyen dikis malzemesine karsi olusan doku yanitinin tavsan modelinde incelenmesi.

OBJECTIVES: We evaluated the inflammatory reactions induced by three commonly used nonabsorbable suture materials in a rabbit model. METHODS: Three suture materials were tested: braided polyester suture (Ethibond), braided blend of polyester and polyethylene suture (FiberWire), and monofilament polypropylene suture (Polypropylene). Thirty-six rabbits were randomly allocated to three suture groups, equal in number. Each suture type was placed bilaterally in the quadriceps muscle, patellar tendon, knee joint capsule, and Achilles tendon. Six animals in each group were sacrificed in the third and sixth weeks. The inflammation induced by each suture was assessed using light microscopy and the width of the inflammation zone (WIZ) was measured. RESULTS: Ethibond was found to cause the most severe reaction in the muscle and tendon in the third week; in the sixth week, however, it showed the lowest inflammatory reaction in all tissue types. Reaction to Propylene was moderate in the third week, whereas it caused the largest WIZ in all tissue types in the sixth week, such that the eventual size of the WIZ induced by Propylene (6.6 + or - 2.1 mm) was significantly greater than that of Ethibond (1.6 + or - 0.9 mm) in muscle specimens (p<0.05). Except for the largest WIZ seen in joint capsule specimens in the third week, inflammatory reactions associated with FiberWire were low or moderate in all tissue specimens throughout the study. FiberWire was associated with some necrotic areas in two muscle and one tendon specimens. CONCLUSION: The extent of inflammatory reaction to nonabsorbable suture materials depends on the type of suture material, tissue type, and the duration of postoperative time.

Histomorphometric evaluation of implants coated with enamel or dentine derived fluoride-substituted apatite.

OBJECTIVES: The aim of this study was to compare osseous healing characteristics of titanium implants coated with enamel-derived fluoride-substituted apatite (EFSA) or dentin-derived fluoride-substituted apatite (DFSA). METHODS: Fluoride-substituted apatite was derived from extracted human teeth with calcination method at 850 degrees C. DFSA and EFSA were separated and carefully ground with a blade grinder. Twenty-four titanium implants were prepared from a 99.99% pure titanium bar. EFSA and DFSA powders were sprayed separately on implants. As control group, unsprayed and sandblasted pure titanium implants were used. Eight adult rams were used in the study. One EFSA coated, 1 DFSA coated and 1 control implants were placed into right tibia of each rams. The rams were sacrificed after 6 months of healing. Undecalcified sections were prepared according to Donath's method and histomorphometric evaluation of implants was made. RESULTS: The mean bone contact percentage of DFSA-coated, EFSA-coated and control implants was 89.88%+/-2.34, 70.19%+/-13.11 and 53.12%+/-5.76 respectively. This study suggests that DFSA-coated implants achieved better bone contact than EFSA-coated implants (P<0.05). Also study groups presented better bone contact than control group (P<0.05). CONCLUSIONS: The results of this study show that although DFSA-coated implants achieved better bone contact, both DFSA and EFSA can be considered as appropriate coating materials.

Time-dependent changes in failure loads of 3 biceps tenodesis techniques: in vivo study in a sheep model.

BACKGROUND: Failure load of the tendon-fixation material-bone unit has a crucial importance for the rehabilitation protocol after tenodesis procedures. PURPOSE: To investigate and compare the time-dependent changes in fixation strengths of 3 proximal biceps tenodesis techniques. STUDY DESIGN: Controlled laboratory study. METHODS: Two intraosseous techniques (suture sling and tenodesis screw) and 1 extraosseous technique (2 suture anchors) were investigated. Biceps tenodesis was performed on 45 shoulders of 26 sheep, 15 shoulders for each technique. Twelve similar cadaveric sheep shoulders (4 for each technique) provided the day 0 results. Sheep were sacrificed at 3, 6, and 9 weeks, and specimens were tested for the failure load of the tenodeses. RESULTS: All 3 tenodesis techniques were found to have similar failure loads at all time intervals tested. All 3 curves remained below the failure load of the intact tendon (862 +/- 96 N) and above their day 0 results for the study period; similarly, at each time interval, results tended to be better compared to the previous test. The tenodesis screw group exhibited significantly higher failure loads at week 3 (419 +/- 53 N) compared to day 0 values (164 +/- 45 N) (P = .009). The same level of significance was observed at week 6 in the remaining 2 groups. CONCLUSION: Tenodesis of the biceps tendon on the proximal humerus at an extra-articular site does not weaken after surgery. The tenodesis screw group had a significantly higher increase in the fixation strength within the first 3 weeks. CLINICAL RELEVANCE: No significant differences could be found between the failure loads of all 3 investigated tenodeses for the first 9 weeks.

Semirapid maxillary expansion--a study of long-term transverse effects in older adolescents and adults.

A new approach, namely, semirapid maxillary expansion (SRME) was introduced with the hypothesis that SRME may stimulate the adaptation process in the nasomaxillary complex and thus would result in reduction of relapse in the postretention period. The aim of this study was therefore to evaluate the short- and long-term effects of SRME on dentofacial structures in older adolescents and adults. The study sample consisted of 40 individuals, 20 orthodontic patients who required maxillary expansion and 20 control cases who received no orthodontic treatment. The mean ages were 14.57 and 13.83 years at the start of treatment and control periods, respectively, and ranged between MP3cap and Ru hand-and-wrist maturation stages. A rigid acrylic maxillary expander was used for SRME (RME of 5-7 days, followed by slow maxillary expansion). The mean expansion time was 0.34 years, and the mean follow-up period was 2.68 years after retention. PA cephalometric film measurements were performed, and the data were analyzed statistically by using paired and Student's t-tests. Lower nasal and maxillary base widths, and upper intermolar and incisor interapex widths were significantly increased compared with the control group (P < .05, P < .001) and remained unchanged during the retention and follow-up stages. Moreover, significant amount of increases occurred in zygomatic and lower nasal widths during the follow-up period. The findings of this study suggested that the dentoskeletal changes after the use of SRME were maintained satisfactorily in the long term in older adolescents and adults.

Failure strength of bioabsorbable interference screws: effects of in vivo degradation for 12 weeks.

We investigated the effect of in vivo degradation for 6-12 weeks on the fixation strength of polylactide bioabsorbable interference screws. Ten bioabsorbable interference screws were used to fix the patellar tendon autograft in ten live sheep knees, which were equally divided into two groups and killed in the 6th or 12th week. The control group consisted of four cadaveric knees. Following the killing of the animals the screws were retrieved and reused to fix patellar tendon grafts in cadaveric sheep knees. Tendon pull-out tests were performed for the partially degraded screws, for the control group, and for the reused screws of the control group. Macroscopic and microscopic examinations of the 6- and 12-week specimens were performed. Tendons pulled-out with an average force of 357+/-30 N in the cadaveric control group on the first use and with 465+/-118 N on the second use. The partially degraded screws failed with a mean load of 399+/-119 N in the 6-week group, and 12-week screws at 447+/-72 N. No macroscopic sign of degradation was observed on the retrieved screws. Histological examination of the 6 week specimens showed necrotic changes in the tendon around screw contact areas. Healing with granulation tissue was present in the same area in the 12th week. Foreign body reaction or an excessive inflammatory reaction was not observed. In vivo degradation of poly- l-lactide interference screws for 12 weeks thus causes neither a loss in the fixation strength of the screws nor an obvious inflammatory reaction.

Low-cost antibiotic loaded systems for developing countries.

Treatment of osteomyelitis with local antibiotic delivery systems has become a common practice in orthopaedic surgery. This study attempted to show that locally produced pure or bioglass reinforced plaster of Paris, hydroxyapatite and sodium alginate are promising biomaterials and mainly because of economical reasons and availability, may be an alternative in clinical practice, especially for developing countries. A total of 32 rabbits were divided into four groups (n:8). In group A, sodium alginate + cephazoline; in group B, plaster of Paris + bioglass + cephazoline; in group C, plaster of Paris + hydroxyapatite + cephazoline and in group D, plaster of Paris + cephazoline were used. The blood serum cephazoline concentrations were analyzed by high performance liquid chromatography on days 1 to 10 everyday and then at days 13, 17, 18, 24, 25 and 30. The mean values +/- standard deviations and median values of blood serum antibiotic concentrations for groups A, B, C and D were 1.45 +/- 0.40 (1.42) mcg/ml, 1.53 +/- 0.64 (1.31) mcg/ml, 1.92 +/- 0.39 mcg/ml (1.90) and 1.41 +/- 0.65 (1.25) mcg/ml, respectively. The detected antibiotic level was constantly over the minimum inhibitory concentration for Staphylococcus aureus. In conclusion, it can be stated that these materials are promising as a antibiotic delivery system even with simple production methods.