Mechanical and biological properties of polymer materials for oral appliances produced with additive 3D printing and subtractive CAD-CAM techniques compared to conventional methods: a systematic review and meta-analysis.

OBJECTIVES: The aim of this review was to analyze mechanical and biological properties of resin materials used with subtractive or additive techniques for oral appliances fabrication and compare them to those conventionally manufactured. MATERIALS AND METHODS: The protocol was registered online at Open Science Framework (OSF) registries ( https://osf.io/h5es3 ) and the study was based on the preferred reporting items for systematic review and meta-analysis protocols (PRISMA-P). An electronic search was conducted on MEDLINE (via PubMed), Scopus, and Web of Science from 1 February 2022 to 1 May 2022. INCLUSION CRITERIA: in vitro and in vivo studies published in the last 10 years, with CAD-CAM or 3D printed resins for occlusal splints. Data considered homogenous were subjected to meta-analysis (95% confidence interval [CI]; α = 0.05) with Stata17 statistical software. Since all variables were continuous, the Hedge g measure was calculated. A fixed-effects model was used for I2 = 0%, while statistical analysis was conducted using a random-effects model with I2 > 0%. RESULTS: 13 studies were included after full-text reading. The mechanical properties most studied were wear, flexural strength, surface hardness and surface roughness, while only 1 study investigated biological properties, performing the XTT viability assay. For the meta-analysis, only surface roughness, volume loss, and flexural strength were selected. Considering surface roughness, the subtractive specimen had a lower average value compared to traditional ones (Hedge's g with 95% CI = -1.25[ -1.84, - 0.66]). No significant difference was detected in terms of volume loss (P > 0.05) between the groups (Hedge's g with 95% CI = -0.01 [-2.71, - 2.68]). While flexural strength was higher in the control group (Hedge's g with 95% CI = 2.32 [0.10-4.53]). CONCLUSION: 3D printed materials showed properties comparable to conventional resins, while milled splint materials have not shown better mechanical performance compared with conventional heat-cured acrylic resin. Polyetheretherketone (PEEK) have great potential and needs to be further investigated. Biological tests on oral cell populations are needed to confirm the long-term biocompatibility of these materials. CLINICAL RELEVANCE: The use of "mixed splints" combining different materials needs to be improved and evaluated in future research to take full advantage of different characteristics and properties.

[Risk and complication profiles of orthogeriatric patients in elective hip and knee joint replacement]. / Risiko- und Komplikationsprofil orthogeriatrischer Patienten bei elektivem Hüft- und Kniegelenkersatz.

BACKGROUND: The care of geriatric patients undergoing elective orthopedic surgery is becoming increasingly more important due to demographic trends. Compared to geriatric traumatology, however, there are still no established orthogeriatric care models in Germany and therefore hardly any scientific data. The aim of this study was to describe the risk and complication profiles in older patients with elective hip and knee replacements. METHODS: In a prospective study data were collected from orthogeriatric patients with indications for elective hip and knee replacement surgery who fulfilled defined inclusion and exclusion criteria between January 2021 and August 2023 in the orthopedic department of a German university hospital for the descriptive analysis of risk and complication profiles. In addition to a preoperative and perioperative data analysis, a follow-up was conducted 4-6 weeks and 3 months postoperatively. RESULTS: The surgical risk profile of the patient population analyzed was characterized by advanced age (78.4 ± 4.8 years), preobesity/obesity (76%), multimorbidity (7.4 ± 3.1 comorbidities), polypharmacy (7.5 ± 3.8 medications), immobility (short physical performance battery 7.1 ± 2.6), prefrailty/frailty (87%), frequent anticoagulation (22%) and a high number of potentially inappropriate medications (64%). Complication events mainly occurred within the first 7 days postoperatively and 90% of the events within this recording period were minor complications. The overall complication rate significantly decreased in the follow-up period. CONCLUSION: Due to the high risk and complication profiles the routine use of orthogeriatric co-management models for elective orthopedic surgery should be considered in the future.

The impact of elective total hip and knee arthroplasty on physical performance in orthogeriatric patients: a prospective intervention study.

BACKGROUND: Osteoarthritis is a prevalent condition in older adults that leads to reduced physical function in many patients and ultimately requires hip or knee replacement. The aim of the study was to determine the impact of hip and knee arthroplasty on the physical performance of orthogeriatric patients with osteoarthritis. METHODS: In this prospective study, we used data from 135 participants of the ongoing Special Orthopaedic Geriatrics (SOG) trial, funded by the German Federal Joint Committee (GBA). Physical function, measured by the Short Physical Performance Battery (SPPB), was assessed preoperatively, 3 and 7 days postoperatively, 4-6 weeks and 3 months after hip and knee arthroplasty. For the statistical analysis, the Friedman test and post-hoc tests were used. RESULTS: Of the 135 participants with a mean age of 78.5 ± 4.6 years, 81 underwent total hip arthroplasty and 54 total knee arthroplasty. In the total population, SPPB improved by a median of 2 points 3 months after joint replacement (p < 0.001). In the hip replacement group, SPPB increased by a median of 2 points 3 months after surgery (p < 0.001). At 3 months postoperatively, the SPPB increased by a median of 1 point in the knee replacement group (p = 0.003). CONCLUSION: Elective total hip and knee arthroplasty leads to a clinically meaningful improvement in physical performance in orthogeriatric patients with osteoarthritis after only a few weeks. TRIAL REGISTRATION: This study is part of the Special Orthopaedic Geriatrics (SOG) trial, German Clinical Trials Register DRKS00024102. Registered on 19 January 2021.

Delay of total joint replacement is associated with a higher 90-day revision rate and increased postoperative complications.

PURPOSE: Delay of elective surgeries, such as total joint replacement (TJR), is a common procedure in the current pandemic. In trauma surgery, postponement is associated with increased complication rates. This study aimed to evaluate the impact of postponement on surgical revision rates and postoperative complications after elective TJR. METHODS: In a retrospective analysis of 10,140 consecutive patients undergoing primary total hip replacement (THR) or total knee replacement (TKR) between 2011 and 2020, the effect of surgical delay on 90-day surgical revision rate, as well as internal and surgical complication rates, was investigated in a university high-volume arthroplasty center using the institute's joint registry and data of the hospital administration. Moreover, multivariate logistic regression models were used to adjust for confounding variables. RESULTS: Two thousand four hundred and eighty TJRs patients were identified with a mean delay of 13.5 ± 29.6 days. Postponed TJR revealed a higher 90-day revision rate (7.1-4.5%, p < 0.001), surgical complications (3.2-1.9%, p < 0.001), internal complications (1.8-1.2% p < 0.041) and transfusion rate (2.6-1.8%, p < 0.023) than on-time TJR. Logistic regression analysis confirmed delay of TJRs as independent risk factor for 90-day revision rate [OR 1.42; 95% CI (1.18-1.72); p < 0.001] and surgical complication rates [OR 1.51; 95% CI (1.14-2.00); p = 0.04]. CONCLUSION: Alike trauma surgery, delay in elective primary TJR correlates with higher revision and complication rates. Therefore, scheduling should be performed under consideration of the current COVID-19 pandemic. LEVEL OF EVIDENCE: Level III-retrospective cohort study.

Arthrosis diagnosis and treatment recommendations in clinical practice: an exploratory investigation with the generative AI model GPT-4.

BACKGROUND: The spread of artificial intelligence (AI) has led to transformative advancements in diverse sectors, including healthcare. Specifically, generative writing systems have shown potential in various applications, but their effectiveness in clinical settings has been barely investigated. In this context, we evaluated the proficiency of ChatGPT-4 in diagnosing gonarthrosis and coxarthrosis and recommending appropriate treatments compared with orthopaedic specialists. METHODS: A retrospective review was conducted using anonymized medical records of 100 patients previously diagnosed with either knee or hip arthrosis. ChatGPT-4 was employed to analyse these historical records, formulating both a diagnosis and potential treatment suggestions. Subsequently, a comparative analysis was conducted to assess the concordance between the AI's conclusions and the original clinical decisions made by the physicians. RESULTS: In diagnostic evaluations, ChatGPT-4 consistently aligned with the conclusions previously drawn by physicians. In terms of treatment recommendations, there was an 83% agreement between the AI and orthopaedic specialists. The therapeutic concordance was verified by the calculation of a Cohen's Kappa coefficient of 0.580 (p < 0.001). This indicates a moderate-to-good level of agreement. In recommendations pertaining to surgical treatment, the AI demonstrated a sensitivity and specificity of 78% and 80%, respectively. Multivariable logistic regression demonstrated that the variables reduced quality of life (OR 49.97, p < 0.001) and start-up pain (OR 12.54, p = 0.028) have an influence on ChatGPT-4's recommendation for a surgery. CONCLUSION: This study emphasises ChatGPT-4's notable potential in diagnosing conditions such as gonarthrosis and coxarthrosis and in aligning its treatment recommendations with those of orthopaedic specialists. However, it is crucial to acknowledge that AI tools such as ChatGPT-4 are not meant to replace the nuanced expertise and clinical judgment of seasoned orthopaedic surgeons, particularly in complex decision-making scenarios regarding treatment indications. Due to the exploratory nature of the study, further research with larger patient populations and more complex diagnoses is necessary to validate the findings and explore the broader potential of AI in healthcare. LEVEL OF EVIDENCE: Level III evidence.

Biological effects of cannabidiol on human cancer cells: Systematic review of the literature.

This systematic review examine the biological effects of CBD, a major component of therapeutic Cannabis, on human pathological and cancer cell populations of integumentary, gastro-intestinal, genital and breast, respiratory, nervous, haematopoietic and skeletal districts in terms of cell viability, proliferation, migration, apoptosis, inflammation, metastasis, and CBD receptor expression. The included studies were in English, on human cell lines and primary culture from non-healthy donors with CBD exposure as variable and no CBD exposure as control. Quality assessment was based on ToxRtool with a reliability score ranging from 15 to 18. Following the PRISMA statement 4 independent reviewers performed an electronic search using MEDLINE via PubMed, Scopus and Web of Science. From 3974 articles, 83 studies have been selected. Data showed conflicting results due to different concentration exposure, administrations and time points. CBD inhibited cell viability and proliferation in most cellular districts except the integumentary apparatus. Also a significant inhibition of migration was observed in all cell types, while an increase in apoptosis at both high and low doses (greater and less than 10 µM respectively). Considering inflammation, CBD caused an anti-inflammatory effect on nervous cells at low doses and on gastro-intestinal cells at high doses, while metastatic power was reduced even at low doses, but in a skeletal cell line there was an increased angiogenesis. CB1 receptor has been related to viability effects, CB2 to apoptosis and TRPV1 to inflammation and invasiveness. A detailed insight into these aspects would allow therapeutic use of this substance without possible side effects.

Mechanical properties of 3D-printed prosthetic materials compared with milled and conventional processing: A systematic review and meta-analysis of in vitro studies.

STATEMENT OF PROBLEM: Three-dimensional (3D) additive manufacturing (AM) is an evolving technology in dentistry, proposed as an alternative to subtractive milling manufacture (MM) or conventional processing. However, a systematic review of the use of AM technology instead of milling or conventional processing is lacking. PURPOSE: The purpose of this systematic review and meta-analysis was to evaluate the mechanical properties of 3D-printed prosthetic materials compared with MM and conventional techniques. MATERIAL AND METHODS: An electronic search of the literature was conducted on the MEDLINE (via PubMed), Scopus, and Web of Science databases. The inclusion criteria were in vitro studies published in the last 5 years, in English or Italian, and with 3D AM printed dental prosthetic materials. Data extraction was focused on dental prosthetic materials (ceramics, polymers, and metals) and their mechanical properties: flexural strength, fracture load, hardness, roughness, removable partial denture (RPD) fit accuracy, trueness, marginal discrepancy, and internal fit. Data considered homogenous were subjected to meta-analysis using the Stata17 statistical software program (95% confidence interval [CI]; α=.05). Since all variables were continuous, the Hedge g measure was calculated. A fixed-effects model was used for I2=0%, while the statistical analysis was conducted using a random-effects model with I2>0%. RESULTS: From a total of 3624 articles, 2855 studies were selected, and 76 studies included after full-text reading. The roughness of AM-printed ceramics generally increased compared with that of conventional processing while the marginal discrepancy was comparable both for ceramics and polymers. The flexural strength, hardness, and fracture load of AM-printed polymers were statistically lower than those of the conventional group (P<.05). No significant difference was detected in terms of hardness, roughness, marginal discrepancy, fracture load, trueness, or internal fit between the AM and MM techniques (P>.05). Milling techniques showed significantly higher values of flexural strength (Hedge g=-3.88; 95% CI, -7.20 to -0.58; P=.02), also after aging (Hedge g=-3.29; 95% CI, -6.41 to -0.17; P=.04), compared with AM printing. CONCLUSIONS: AM is comparable with MM in terms of mechanical properties, in particular with polymeric materials. The flexural strength of AM-printed prostheses is lower than with conventional and MM techniques, as are the parameters of hardness and fracture load, while the marginal discrepancy is similar to that of MM and conventional techniques. AM prostheses are commonly used for interim crowns and fixed partial dentures, as their rigidity and fracture resistance cannot support mastication forces for extended periods. More comparative studies are needed.

Heat-not-burn tobacco (IQOS), oral fibroblasts and keratinocytes: cytotoxicity, morphological analysis, apoptosis and cellular cycle. An in vitro study.

OBJECTIVES: The aim of this work is to investigate the biological effects of IQOS smoking on human gingival fibroblasts and human keratinocytes analysing cell viability, morphology, migration, apoptosis and cell cycle. BACKGROUND: Electronic cigarettes and tobacco heating systems have been marketed to reduce smoking damages caused by combustion. METHODS: Human gingival fibroblasts and human keratinocytes viability was determined by a colorimetric assay measuring mitochondrial dehydrogenase activity (MTT assay); after an in vitro exposure of 24 h, cell morphology was analysed with scanning electron microscope and cell migration was tested by Scratch assay, a method to mimic the migration of the cells during wound healing in vivo. Apoptosis and cell cycle were analysed with flow cytometry, and the expression of related genes (p53, Bcl2, p16 and p21) was indagated using real-time polymerase chain reaction. RESULTS: IQOS extracts increased both cell viability (23%-41% with fibroblasts and 30%-79% with keratinocytes) and migration. No morphological alterations were observed. IQOS extracts did not induced an increase in cell death, but rose the number of S- and G2/M-phase cells. IQOS extracts also significantly increased p53 expression by fibroblasts (undiluted and 6.25% dilution, 2- and 3.6-fold higher, respectively) and reduced both Bcl2 (about two- and fivefold, respectively) and p21 expressions (about twofold with both extracts), while on keratinocytes both undiluted and 6.25% dilution extracts increased Bcl2 expression (about four- and threefold higher, respectively) and reduced p53 expression (about two- and fivefold, respectively). CONCLUSION: IQOS smoke seemed to induce proliferation as highlighted by a viability assay, and migration and cell cycle analysis. The increased cell proliferation induced by IQOS devices must be carefully investigated for its possible clinical effects on oral cell populations.

Morpho-functional effects of different universal dental adhesives on human gingival fibroblasts: an in vitro study.

To analyze the effects of four universal adhesives (Optibond Solo Plus-OB, Universal Bond-UB, Prime&Bond Active-PBA, FuturaBond M + -FB) on human gingival fibroblasts in terms of cytotoxicity, morphology and function. After in vitro exposure for up to 48 h, fibroblast viability was determined by the MTT assay determined, morphology by phase-contrast microscopy and migration by the scratch wound assay. Expression levels of IL1ß, IL6, IL8, IL10, TNFα and VEGF genes were assessed by RT-PCR and their protein production by Western blot analysis. Apoptosis and cell cycle were analyzed by flow cytometry. OB and UB induced early morphological changes on fibroblasts (3 h) with extended cell death at 24 h/48 h. Gene expression of collagen type I and fibronectin increased fivefold compared with controls, elastin disappeared and elastase increased threefold, indicating gingival tissue tended to become fibrotic. Only UB and OB increased gene expression of inflammatory markers: IL1ß at 3 and 48 h (up to about three times), IL6 and IL8 at 3 h (up to almost four times) which corresponded to the increase of the activated form NF-kB. All adhesives showed an effect on the functionality of fibroblasts with cytotoxic effect time and concentration dependent. Among all the OB and UB adhesives, they showed the greatest cell damage. The in-depth analysis of the effects of universal adhesives and possible functional effects represents an important information for the clinician towards choosing the most suitable adhesive system.

Individual 3-dimensional printed mold for treating hard palate carcinoma with brachytherapy: A clinical report.

This clinical report describes the use of a 3-dimensional (3D) printer to create an individual mold for delivering high-dose-rate interventional radiotherapy for hard palate cancer. The maxillary teeth and palate were scanned with an intraoral scanner (3Shape TRIOS 3). The scan was transformed into a mesh using the standard tessellation language (STL) format and aligned with Digital Imaging and Communications in Medicine (DICOM) computed tomography (CT) images using free Blue Sky Plan 4 planning software. A mold was generated by tracing a guideline around the gingival margins of the maxillary teeth and palate on the scan mesh in accordance with established parameters. All data were imported into computer-aided design (CAD) software. For this patient, 3 parallel 2.2-mm-diameter ducts were placed 10 mm from each other in the mold mesh. A CT scan of the patient's mouth with the mold in place was used for treatment planning. Treatment was delivered by means of microSelectron digital afterloading.

Lasers for caries removal in deciduous and permanent teeth.

BACKGROUND: Despite considerable improvements in oral health, dental caries continue to be a public health issue. The most frequently used, and universally accepted technique, to remove caries is through mechanical ablation of decayed tissues by means of rotating drills (diamond or tungsten carbide, or both). In the past few decades, the introduction of adhesive filling materials (resin composites) has affected cavity filling procedures by reducing its retention needs, with advantages for dental tissue conservation. Consequently, new minimally invasive strategies were introduced into dental practice, such as the use of lasers to perform highly controlled tissue ablation. Laser use has also raised expectations of limiting pain and discomfort compared to using drills, as well as overcoming drill phobia. OBJECTIVES: The main objective of the review was to compare the effects of laser-based methods to conventional mechanical methods for removing dental caries in deciduous and permanent teeth. SEARCH METHODS: We searched the following electronic databases: Cochrane Oral Health's Trials Register (searched 22 June 2016), Cochrane Central Register of Controlled Trials (CENTRAL; 2016, Issue 5) in the Cochrane Library (searched 22 June 2016), MEDLINE Ovid (1946 to 22 June 2016), Embase Ovid (1980 to 22 June 2016), ProQuest Dissertations and Theses (1980 to 22 June 2016), Zetoc (limited to conference proceedings) (1993 to 22 June 2016), and ISI Web of Knowledge (limited to conference proceedings) (1990 to 22 June 2016). We checked the reference lists of relevant articles to identify additional studies. We searched the US National Institutes of Health Ongoing Trials Register ClinicalTrials.gov and the World Health Organization International Clinical Trials Registry Platform for ongoing trials. SELECTION CRITERIA: We included randomised controlled trials, split-mouth trials and cluster-randomised trials (irrespective of their language) comparing laser therapy to drill ablation of caries. We included participants of any age (children, adolescents and adults). DATA COLLECTION AND ANALYSIS: Two review authors independently screened titles and abstracts of citations identified by the review search strategy. Two review authors independently evaluated the full text of relevant primary studies, assessed risk of bias and extracted data. We used standard methodological procedures expected by Cochrane. MAIN RESULTS: We included nine randomised trials, published between 1998 and 2014, involving 662 participants. The population consisted of both children and adolescents in four trials, only adults in four trials, and both children/adolescents and adults in one trial. Four studies examined only permanent teeth, and five studies evaluated both deciduous and permanent teeth. Six trials used Er:YAG (erbium-doped yttrium aluminium garnet) lasers, two trials employed Er,Cr:YSGG (erbium, chromium: yttrium-scandium-gallium-garnet) lasers, and one trial used Nd:YAG (neodymium-doped yttrium aluminium garnet) laser.Overall, the trials had small sample sizes, and the majority were at unclear or high risk of bias. The primary outcomes were evaluated in a limited number of trials (removal of caries (four trials (but only two reported quantitative data)); episodes of pain (five studies)). There was insufficient evidence to suggest that either lasers or drill were better at caries removal (risk ratio (RR) 1.00, 95% confidence interval (CI) 0.99 to 1.01; 2 studies; 256 treated caries; P = 0.75; I2 = 0%; low-quality evidence).The incidence of moderate or high pain was greater in the drill group compared to the laser group (RR 0.40, 95% CI 0.28 to 0.57; 2 studies; 143 participants; P < 0.001; I2 = 50%). Similarly, the need for anaesthesia was significantly higher in the drill group than in the laser group (RR 0.25, 95% CI 0.10 to 0.65; 3 studies; 217 children/adolescents; P = 0.004; I2 = 0%).In terms of marginal integrity of restoration, there was no evidence of a difference between laser and drill comparisons evaluated at 6 months (RR 1.00, 95% CI 0.21 to 4.78; 3 studies), 1 year (RR 1.59, 95% CI 0.34 to 7.38; 2 studies), or 2 years (RR 1.00, 95% CI 0.21 to 4.74; 1 study).There was no evidence of a difference for durability of restoration between laser therapy or drill at 6 months' follow-up (RR 2.40, 95% CI 0.65 to 8.77; 4 studies), at 1 year (RR 1.40, 95% CI 0.29 to 6.78; 2 studies) or at 2 years' follow-up (RR 0.50, 95% CI 0.02 to 14.60; 1 study).Only two trials investigated the recurrence of caries, but no events occurred during 6 months' follow-up.There was insufficient evidence of a difference between laser or drill in terms of pulpal inflammation or necrosis at 1 week (RR 1.51, 95% CI 0.26 to 8.75; 3 studies) and at 6 months (RR 0.99, 95% CI 0.10 to 9.41; 2 studies). AUTHORS' CONCLUSIONS: Given the low quality of the body of evidence, we concluded that evidence was insufficient to support the use of laser as an alternative to traditional drill therapy for caries removal. We found some evidence in favour of laser therapy for pain control, need of anaesthesia and patient discomfort, but, again, the body of evidence was of low quality. Additional well-designed, randomised trials investigating the most relevant outcomes are needed.

Scanning Electron Microscopy Evaluation of Dental Root Resorption Associated With Granuloma.

The inflammatory resorption of dental root apex (i.e., the process of removal of cementum and/or dentine through the activity of resorbing cells) may show different configurations and damage the apical root structure. As knowing the morphology of resorption areas of human teeth is essential for the success of endodontic treatments, we investigated the apical resorption by scanning electron microscopy, focusing on roots with granulomas. A total of 30 teeth (with penetrating carious lesions and chronic periapical lesions) were examined, the apical third of the roots were removed and analyzed to estimate periforaminal and foraminal resorption, shape and morphology of foramen resorption, centering of the periforaminal resorption area, and diameters of each apical foramen. Periforaminal resorption was present in all samples, whereas foraminal resorption was present in 92% of cases (mainly funnel shaped). Lacunae were observed in the foraminal resorption area with an average diameter of 35±14 µm. The major and minor diameters of the foramina in teeth with resorption were 443 and 313 µm, respectively (higher than in healthy teeth). This result indicates an expansion of the apical diameters caused by the pathology, which could encourage a different clinical instrumentation for these teeth.

Methamphetamine abuse and "meth mouth" in Europe.

With easy chemical synthesis from its precursor, methamphetamine (MA) is now widespread in many countries. The abuse of methamphetamine is associated with several negative effects on health, because MA is a neurotoxin and a dangerous central nervous system stimulant. It changes levels of neurotransmitters in the brain, releasing dopamine and inhibiting nor epinephrine uptake which increases sympathetic nervous system activity and can lead to cardiac arrhythmia, hypertension and tachypnea. The consequences of MA abuse are clearly manifested in oral diseases (like "meth mouth") which is characterised by extensive caries, teeth grinding with ensuing dental wear and trismus. The present review was designed to fill the gap in knowledge about methamphetamine abuse in the European Union (EU) and to illustrate the main clinical effects of prolonged use. After describing the pharmacology and systemic effects of methamphetamine and concentrating on its effects on the mouth, the present review compares the epidemiology and incidence of abuse in the world, particularly the USA and the EU.

Johann Baptist Spix and the "lingula mandibularis".

Johann Baptist Ritter von Spix (1781-1826), a German zoologist, was famous in his time and highly honored after making one of the first exploration voyages in the wildest part of Brazil. He was almost forgotten in the annals of history for nearly two centuries after his birth, at which time some enlightened biographers brought him back into prominence in both the biological and zoological fields. On the contrary though, he had never been forgotten in the science of odontostomatology thanks to his discovery of the "Lingula Mandibularis" also known as "Spine of Spix". Johannes Baptist Spix was born in Hoechstadt, Germany in 1781. He was the Conservator of the Museum of Natural History in Munich and was a distinguished Comparative Anatomist. He died Munich inl 1826. The purposes of this work are to present some biographical notes on J.B. Ritter von Spix, to explain whythe "Lingula Mandibularis" has been called by the name of Spix and why this eponym has been used as such.

[Navigated or conventional acetabular surgery : Comparison of positional accuracy exemplified by the infra-acetabular screw]. / Navigiert oder konventionell in der Acetabulumchirurgie : Vergleich der Positionsgenauigkeit am Beispiel der infraazetabulären Schraube.

BACKGROUND: The principle of joint-preserving treatment of acetabular fractures is the anatomic reduction of joint-bearing elements and internal osteosynthesis. For stabilization of the anterior and posterior columns against each other, the infra-acetabular screw (IAS) is regularly used in the clinical routine. OBJECTIVE: The aim of this study was to compare the position of the IAS in the infra-acetabular corridor after navigated placement and after freehand placement. MATERIAL AND METHOD: The position of the screw was evaluated in 42 patients using multiplanar reconstructions. The screw was placed freehand in 30 patients and using image-guided navigation in 12 patients. In addition to measurement of the position of the screw, demographic data, operating time, radiation exposure and blood loss were recorded. RESULTS: The vast majority of the patients were male (86%), the median age was 67 years and the median body mass index (BMI) was 25 kg/m2. The median operating time was 166 min and the median blood loss was 900 ml. The adjusted values in the whole sample considering the position of the screw were: distance of screw to cartilage mean value (m) = 3.8 mm, distance of screw to corridor center m = 3.5 mm and angle of screw to corridor m = 1.4°. There were no differences between the groups in the demographic parameters and the accuracy of positioning of the screw (p-value > 0.05). There was a longer irradiation time and a higher radiation dose in the navigated group compared to the group without navigation (p-value < 0.001). CONCLUSION: With appropriate experience both procedures are comparable taking into account the accuracy. Taking into consideration other perioperative parameters, such as radiation exposure and planned operating time, patient-related factors should be taken into consideration.

[Navigation and robotics-current status and future implications]. / Navigation und Robotik ­ status präsens und zukünftige Implikationen.

INTRODUCTION: Both navigation systems and robotics enable greater precision in the implantation of an artificial knee joint. However, they do not improve clinical outcomes. We hypothesized that although implantation of a total knee arthroplasty results in reconstruction of the alignment in the coronal plane, the variable rotational tibial and variable translational femoral and tibial component positioning lead to a change in the remaining alignment parameters of the lower extremity. However, these parameters could be determined using a navigation system or robot and could represent future implications for these systems. METHODS: The kinematics and the position between femur and tibia before and after implantation of a total knee arthroplasty were determined using a navigation system in nine healthy knee joints of Thiel-fixed whole-body cadavers. RESULTS: After arthroplasty, there was no change in the natural coronal alignment. In extension and the early degrees of flexion, the rotational position of the femur relative to the tibia was altered. This also led to a change in the positioning of the medial and lateral epicondyle in relation to the tibia; while both epicondyles were positioned more laterally in relation to the tibia after arthroplasty, the lateral epicondyle was significantly more lateral in relation to the tibia up to 20° of flexion. DISCUSSION: Following arthroplasty of a knee joint using the established technique, a good reconstruction of the coronal alignment was achieved with simultaneous changes in the alignment in both the rotational and translational directions between the femur and tibia. Using navigation as well as robotics, we would be able to quantify all alignment parameters and could achieve an alignment of the components or a reconstruction of the overall alignment in all six degrees of freedom. We might also be able to achieve a clinical advantage or increase the service life even further.

An evaluation of the Invisalign® Aligner Technique and consideration of the force system: a systematic review.

OBJECTIVE: Since its introduction 25 years ago, the Invisalign® system has undergone multiple digital and biomechanical evolutions and its effectiveness is often compared to traditional systems without considering the many differences which characterize them. The main aim of this systematic review is to look at the literature dealing with studies on teeth movements using the Invisalign® system and the management of these movements through digital planning and artificial intelligence. MATERIALS AND METHODS: The following electronic databases were searched: MEDLINE, Embase, the Cochrane Oral Health Group's Trials Register, and CENTRAL. Unpublished studies were searched on ClinicalTrials.gov, the National Research Register, and Pro-Quest Dissertation Abstracts and Thesis database. RESULTS: Twenty-four studies (15 retrospective, 5 prospective, 2 pilot, and 2 case-control) were included. The results of the analysis carried out on the available literature show that the Invisalign® system is recognized to be a valid alternative to conventional orthodontic treatment in no-extraction cases. The results are influenced by the methods for assessing the effectiveness of this technique and by the comparison bias of the traditional system with the innovative digital system. CONCLUSIONS: Since the introduction of SmartForce and SmartTrack material, the efficacy of the treatment has improved. There is still a shortage of high-quality evidence concerning the treatment modality. In order to make the treatment with the aligners more efficient, a correct management of the ClinCheck® software and a proper use of the biomechanics are necessary. The aligned force-driven system should be taken into account when developing the digital planning.

Impressive Short-Term Improvement in Functional Outcome and Quality of Life after Primary Total Hip Arthroplasty (THA) in the Orthogeriatric Patient in a Prospective Monocentric Trial.

Background/Objectives: Osteoarthritis (OA) represents the most frequent chronic joint disease worldwide. Facing an aging population, resulting from the demographic change, the number of primary total hip arthroplasties (THA) will further increase. Although the geriatric patient strongly differs from the younger one, the current literature on elective orthopedic surgery in the geriatric patient is scarce. This work analyses, whether geriatric patients receiving primary THA significantly improve in terms of their (1) mobility and functional outcome and (2) health-related quality of life at four to six weeks as well as three months postoperatively. Methods: In a prospective study design, we analyzed 101 geriatric patients with osteoarthritis of the hip receiving primary THA. The study is part of the ongoing "Special Orthopaedic Geriatrics" (SOG) trial, which is funded by the German Federal Joint Committee (GBA). In addition to a preoperative comprehensive geriatric assessment (CGA), the Western Ontario and McMaster Universities Arthritis Index (WOMAC) and the EQ5D-5L were imposed preoperatively (t0), at four to six weeks (t1), and at three months (t2) postoperatively. Results: The 101 enrolled patients had a mean age of 78.1 ± 4.9 years. The total WOMAC score and almost all subcategories significantly improved at four to six weeks as well as three months postoperatively in comparison to the preoperative results (p < 0.001). The same was observed for the EQ-5D-5L, showing significant improvement in overall health at both time points (p < 0.001) and all subcategories (p < 0.05). Conclusions: This study implies that a geriatric patient benefits as much from elective primary THA as a younger patient. However, the preoperative comprehensive geriatric assessment with screening for risk factors is of utmost importance. Regarding the aging population, a lot of effort is needed to obtain more knowledge about geriatric patients receiving elective orthopedic surgery.

Investigation of the precision of a novel jaw tracking system in recording mandibular movements: A preliminary clinical study.

OBJECTIVES: This preliminary study aimed to clinically assess the precision of a novel optical jaw tracking system (JTS) in registering mandibular movements (MMs) of protrusion and mediotrusion. METHODS: Twenty healthy participants underwent recordings using Cyclops JTS (Itaka Way Med) for functional MMs of protrusion and laterotrusion by two trained clinicians. Each subject performed five registrations at different times according to a standardized pattern within one-month period. The angulations of protrusive and mediotrusive functional paths within the first 2 mm from the maximal intercuspal position (MIP) were calculated for each trace, using a data software for angle measurements. Descriptive statistics were used to assess the repeatability of the recordings for each participant and MM. Additionally, inferential statistics were carried out on standard deviation values obtained (α=0.05). RESULTS: The overall precision for all the patients was 7.07±3.37° for the protrusion angle, 5.24±2.24° for right laterotrusion and 5.14±3.06° for left laterotrusion angles. The protrusion angle ranged from 3.08° to 13.57°, while the right and left laterotrusion ranged from 1.82° to 9.42° and from 1.58° to 10.59°, respectively. No statistically significant differences were observed between different functional MM types and gender (p > 0.05). CONCLUSIONS: Recordings functional MMs of mediotrusion and protrusion using Cyclops JTS showed consistent repeatability, regardless of gender and functional MM type. The results revealed non-negligible variations that may be due to the patients' abilities to precisely reproduce jaw movements or to the operator's ability to consistently connect the kinesiograph. CLINICAL SIGNIFICANCE: Capturing functional MMs digitally and importing the data into dental CAD software is essential for virtual waxing in prosthetic rehabilitations to design a functionalized adapted occlusion. Establishing the repeatability of MM recordings by a JTS is a crucial step in better understanding this novel JTS in the market. This process could facilitate the interpretation of cusp angles, aid in CAD dynamic technical modeling, and enhance clinical data communication between clinicians and technicians in a modern workflow.

Midterm survival and risk factor analysis in patients with pyogenic vertebral osteomyelitis: a retrospective study of 155 cases.

Background: Pyogenic vertebral osteomyelitis (VO) represents a clinical challenge and is linked to substantial morbidity and mortality. This study aimed to examine mortality as well as potential risk factors contributing to in-hospital mortality among patients with VO. Methods: This retrospective analysis involved patients receiving treatment for VO at University Regensburg in Germany from January 1, 2000, to December 3, 2020. It included in-hospital mortality rate, comorbidities and pathogens. Patients were identified using ICD-10 diagnosis codes: M46.2, M46.3, M46.4, and M46.5. Kaplan-Meier probability plots and odds ratios (OR) for mortality were calculated. Results: Out of the total cohort of 155 patients with VO, 53 patients (34.1%) died during a mean follow-up time of 87.8 ± 70.8 months. The overall mortality was 17.2% at one year, 19.9% at two years and 28.3% at five years. Patients with congestive heart failure (p = 0.005), renal disease (p < 0.001), symptoms of paraplegia (p = 0.029), and sepsis (p = 0.006) demonstrated significantly higher overall mortality rates. In 56.1% of cases, pathogens were identified, with Staphylococcus aureus (S. aureus) and other unidentified pathogens being the most common. Renal disease (OR 1.85) and congestive heart failure (OR 1.52) were identified as significant risk factors. Conclusion: Early assessment of the specific risk factors for each patient may prove beneficial in the management and treatment of VO to reduce the risk of mortality. These findings demonstrate the importance of close monitoring of VO patients with underlying chronic organ disease and early identification and treatment of sepsis. Prioritizing identification of the exact pathogens and antibiotic sensitivity testing can improve outcomes for patients in this high-risk group.