A comparative assessment of the dentoskeletal effects of clear aligners vs miniplate-supported posterior intrusion with fixed appliances in adult patients with anterior open bite. A multicenter, retrospective cohort study.

INTRODUCTION: This study aimed to retrospectively evaluate the dentoskeletal effects of clear aligners (Invisalign) vs miniplate-supported posterior intrusion (MSPI) and identify factors associated with posttreatment overbite in adults with anterior open bite. METHODS: Twenty-nine patients treated with Invisalign and 24 with MSPI combined with full-fixed orthodontic appliances were included from 5 orthodontic practices. Pretreatment and posttreatment lateral cephalometric measurements were included as outcomes. Comparisons across groups and identification of final overbite predictors were assessed with regression modeling and machine learning techniques. RESULTS: MSPI induced significantly greater maxillary molar intrusion (1.5 mm; 95% confidence interval [CI], 0.83-2.17; P <0.001), with subsequent reduction of anterior face height (ANS-Me) (-2.77 mm; 95% CI, -3.64 to -1.91; P <0.001), Mp-SN° (-1.95°; 95% CI, -2.77 to -1.12; P <0.001), and ANB° (-1.69°; 95% CI, -2.44 to -0.94; P <0.001) compared with Invisalign. MSPI resulted in a significantly larger increase in SNB° (0.94°; 95% CI, 0.23-1.65; P = 0.01) and point-Pog projection (2.45 mm; 95% CI, 1.12-3.77; P = 0.001). Compared with MSPI, Invisalign had a significantly greater increase in the distance of maxillary (1.05 mm; 95% CI, 0.38-1.72; P = 0.003) and mandibular (0.9 mm; 95% CI, 0.19-1.60; P = 0.01) incisal edges relative to their apical bases, with borderline greater lingual tipping of only the maxillary incisors (2.82°; 95% CI, -0.44 to 6.09; P = 0.09). Appliance type and initial overbite were significant final overbite predictors across all models. However, this difference was only evident in male patients (males [1.65; 95% CI, 0.99-2.32; P <0.001]; female [-0.04; 95% CI, -0.52 to 0.44; P = 0.87]). CONCLUSIONS: Both appliances effectively improve overbite. MSPI applied the correction via molar intrusion and counterclockwise mandibular autorotation, whereas Invisalign via maxillary and mandibular incisor extrusion.

A Capacitive Cochlear Implant Electrode Array Sensing System to Discriminate Fold-Over Pattern.

Purpose During insertion of the cochlear implant electrode array, the tip of the array may fold back on itself and can cause serious complications to patients. This article presents a sensing system for cochlear implantation in a cochlear model. The electrode array fold-over behaviors can be detected by analyzing capacitive information from the array tip. Method Depending on the angle of the array tip against the cochlear inner wall when it enters the cochlear model, different insertion patterns of the electrode array could occur, including smooth insertion, buckling, and fold-over. The insertion force simulating the haptic feedback for surgeons and bipolar capacitance signals during the insertion progress were collected and compared. The Pearson correlation coefficient (PCC) was applied to the collected capacitive signals to discriminate the fold-over pattern. Results Forty-six electrode array insertions were conducted and the deviation of the measured insertion force varies between a range of 20% and 30%. The capacitance values from electrode pair (1, 2) were recorded for analyzing. A threshold for the PCC is set to be 0.94 that can successfully discriminate the fold over insertions from the other two types of insertions, with a success rate of 97.83%. Conclusions Capacitive measurement is an effective method for the detection of faulty insertions and the maximization of the outcome of cochlear implantation. The proposed capacitive sensing system can be used in other tissue implants in vessels, spinal cord, or heart.

A Novel Capacitive Cochlear Implant Electrode Array Sensing System to Discriminate Failure Patterns.

OBJECTIVES: The research is to propose a sensing system to ensure the electrode array being correctly placed inside the cochlea. Instead of applying extra sensors to the array, the capacitive information from multiple points of the array is gathered and analyzed to determine the state and behavior of the electrode array. METHODS: The sensing system measures electrode bipolar capacitances between multiple pairs of electrodes during the insertion. The principal component analysis (PCA) method is then applied to analysis the recorded data to discriminate insertion patterns. RESULTS: In total, 384 capacitance profiles from electrode pair (1, 2), and electrode pair (15, 16) were analyzed and compared. In an account of both the electrode pairs, the threshold distance was examined to be d = 1.99 at the average comparison type. The experiment results showed the success rate is over 80% to identify buckling during the insertion on a 2D cochlear model. CONCLUSION: This early-stage investigation shows great potential compared with the current practice, which does not provide any feedback to surgeons. The system demonstrates the feasibility of a sensing method for auto-reoccupation electrodes behavior, and it will help surgeons to avoid misplacement of the electrode array inside the cochlea.

Noise Exposure on Human Cochlea During Cochleostomy Formation Using Conventional and a Hand Guided Robotic Drill.

OBJECTIVE: To investigate the disturbance induced in the cochlea during cochleostomy using conventional drill and a hand guided robotic drill. STUDY DESIGN: The study is based on experimental measurements using the Laser Doppler Vibrometer during the drilling processes converted to Sound Pressure Levels (SPL) for comparison. SETTING: The study is based on experimental results of three sets of cochleostomies on human cadaver heads. MAIN OUTCOME MEASURE(S): Robotic drilling, in comparison to the conventional drilling method, creates a consistently lower level of disturbance in cochlea across the hearing frequency range. RESULTS: Robotic drilling, in comparison to the conventional drilling method, creates a consistently lower level of disturbance in cochlea across the hearing frequency range. CONCLUSIONS: It is reasonable to conclude that robotic drilling has a lower possibility of creating acoustic trauma in cochlea that endangers the residual hearing of patients.

Atypical Mesenchymal Stromal Cell Responses to Topographic Modifications of Titanium Biomaterials Indicate Cytoskeletal- and Genetic Plasticity-Based Heterogeneity of Cells.

Titanium (Ti) is widely used as a biomaterial for endosseous implants due to its relatively inert surface oxide layer that enables implanted devices the ability of assembling tissue reparative components that culminate in osseointegration. Topographic modifications in the form of micro- and nanoscaled structures significantly promote osseointegration and enhance the osteogenic differentiation of adult mesenchymal stromal cells (MSCs). While the biological mechanisms central to the differential responses of tissues and cells to Ti surface modifications remain unknown, adhesion and morphological adaptation are amongst the earliest events at the cell-biomaterial interface that are highly influenced by surface topography and profoundly impact the regulation of stem cell fate determination. This study correlated the effects of Ti topographic modifications on adhesion and morphological adaptation of human MSCs with phenotypic change. The results showed that modified Ti topographies precluded the adhesion of a subset of MSCs while incurring distinct morphological constraints on adherent cells. These effects anomalously corresponded with a differential expression of stem cell pluripotency and Wnt signalling-associated markers on both modified surfaces while additionally differing between hydrophobic and hydrophilic surface modifications-though extent of osteogenic differentiation induced by both modified topographies yielded similarly significant higher levels of cellular mineralisation in contrast to polished Ti. These results suggest that in the absence of deposited proteins and soluble factors, both modified topographies incur the selective adhesion of a subpopulation of progenitors with relatively higher cytoskeletal plasticity. While the presence of deposited proteins and soluble factors does not significantly affect adherence of cells, nanotopographic modifications enhance expression of pluripotency markers in proliferative conditions, which are conversely overridden by both modified topographies in osteogenic inductive conditions. Further deciphering the mechanisms underlying cellular selectivity and Ti topographic responsiveness will improve our understanding of stem cell heterogeneity and advance the potential of MSCs in regenerative medicine.

A hand-guided robotic drill for cochleostomy on human cadavers.

BACKGROUND: An arm supported robotic drill has been recently demonstrated for preparing cochleostomies in a pilot research clinical trial. In this paper, a hand-guided robotic drill is presented and tested on human cadaver trials. METHODS: The innovative smart tactile approach can automatically detect drilling mediums and decided when to stop drilling to prevent penetrating the endosteum. The smart sensing scheme has been implemented in a concept of a hand guided robotic drill. RESULTS: Experiments were carried out on two adult cadaveric human bodies for verifying the drilling process and successfully finished cochleostomy on three cochlea. The advantage over a system supported by a mechanical arm includes the flexibility in adjusting the trajectory to initiate cutting without slipping. Using the same concept as a conventional drilling device, the user will also be benefit from the lower setup time and cost, and lower training overhead. CONCLUSION: The hand-guided robotic drill was recently developed for testing on human cadavers. The robotic drill successfully prepared cochleostomies in all three cases.

The effect of metal ions released from different dental implant-abutment couples on osteoblast function and secretion of bone resorbing mediators.

OBJECTIVES: The etiology of the reduced marginal bone loss observed around platform-switched implant-abutment connections is not clear but could be related to the release of variable amounts of corrosion products. The present study evaluated the effect of different concentrations of metal ions released from different implant abutment couples on osteoblastic cell viability, apoptosis and expression of genes related to bone resorption. METHODS: Osteoblastic cells were exposed to five conditions of culture media prepared containing metal ions (titanium, aluminum, vanadium, cobalt, chromium and molybdenum) in different concentrations representing the amounts released from platform-matched and platform-switched implant-abutment couples as a result of an earlier accelerated corrosion experiment. Cell viability was evaluated over 21days using the Alamar Blue assay. Induction of apoptosis was measured after 24h of exposure using flow cytometry. Expression of interleukin-6, interleukin-8, cyclooxygenase-2, caspase-8, osteoprotegerin and receptor activator of nuclear factor kappa-B ligand (RANKL) by osteoblastic cells were analysed after exposure for 1, 3 and 21days using real-time quantitative polymerase chain reaction assay RESULTS: Metal ions in concentrations representing the platform-matched groups led to a reduction in cell viability (P<0.01) up to 7days of exposure. Stimulated cells showed higher rates of early apoptosis (P<0.01) compared to non-treated cells. Metal ions up-regulated the expression of interleukin-6, interleukin-8, cyclooxygenase-2 and RANKL in a dose dependent manner after 1day of exposure (P<0.05). The up-regulation was more pronounced in the groups containing the corrosion products of platform-matched implant-abutment couples. CONCLUSION: Osteoblastic cell viability, apoptosis, and regulation of bone resorbing mediators were significantly altered in the presence of metal ions. The change in cytokine levels expressed was directly proportional to the metal ion concentration. CLINICAL SIGNIFICANCE: The observed biological responses to decreased amounts of metal ions released from platform-switched implant-abutment couples compared to platform-matched couples may partly explain the positive radiographic findings in respect to crestal bone level when utilising the "platform-switching" concept, which highlights the possible role of corrosion products in the mediation of crestal bone loss around dental implants.

Osteogenic stem cell selection for repair and regeneration.

The first osteogenic cells to attach to a titanium (Ti) implant after placement are the multipotent stromal cells (MSCs) that circulate in the bloodstream and are recruited to the site of tissue damage. The reservoirs of these cells are heterogeneous in nature, consisting of a mixture of cells with varying differentiation abilities. In order to utilise these cells and to reduce the chance of unwanted events during regenerative therapies, the selection of a subset of cells that is truly multipotent is required. The behaviour of these cells has been shown to be altered by modifications to Ti implant surfaces, most notably rough, hydrophilic Ti. These changes in behaviour underpin the differences seen in clinical performance of these surfaces. In this study Human bone marrow derived stromal cells (hBMSCs) have been cultured on modified Ti surfaces in order to analyse these changes in cell behaviour. The results demonstrate the different effects of the surfaces and suggest that one surface selectively enriches the population with osteogenic adult 'stem cells' by inducing the cell death of the more differentiated cells. Combined with subsequent expansion in bioreactors before implantation, this may lead to a new source of cells for regenerative therapies.

Mesenchymal stem cell response to topographically modified CoCrMo.

Surface roughness on implant materials has been shown to be highly influential on the behavior of osteogenic cells. Four surface topographies were engineered on cobalt chromium molybdenum (CoCrMo) in order to examine this influence on human mesenchymal stem cells (MSC). These treatments were smooth polished (SMO), acid etched (AE) using HCl 7.4% and H2SO4 76% followed by HNO3 30%, sand blasted, and acid etched using either 50 µm Al2O3 (SLA50) or 250 µm Al2 O3 grit (SLA250). Characterization of the surfaces included energy dispersive X-ray analysis (EDX), contact angle, and surface roughness analysis. Human MSCs were cultured onto the four CoCrMo substrates and markers of cell attachment, retention, proliferation, cytotoxicity, and osteogenic differentiation were studied. Residual aluminum was observed on both SLA surfaces although this appeared to be more widely spread on SLA50, whilst SLA250 was shown to have the roughest topography with an Ra value greater than 1 µm. All substrates were shown to be largely non-cytotoxic although both SLA surfaces were shown to reduce cell attachment, whilst SLA50 also delayed cell proliferation. In contrast, SLA250 stimulated a good rate of proliferation resulting in the largest cell population by day 21. In addition, SLA250 stimulated enhanced cell retention, calcium deposition, and hydroxyapatite formation compared to SMO (p < 0.05). The enhanced response stimulated by SLA250 surface modification may prove advantageous for increasing the bioactivity of implants formed of CoCrMo.

TiO2-coated CoCrMo: improving the osteogenic differentiation and adhesion of mesenchymal stem cells in vitro.

The current gold standard material for orthopedic applications is titanium (Ti), however, other materials such as cobalt-chromium-molybdenum (CoCrMo) are often preferred due to their wear resistance and mechanical strength. This study investigates if the bioactivity of CoCrMo can be enhanced by coating the surface with titanium oxide (TiO2 ) by atmospheric pressure chemical vapor deposition (CVD), thereby replicating the surface oxide layer found on Ti. CoCrMo, TiO2-coated CoCrMo (CCMT) and Ti substrates were used for this study. Cellular f-actin distribution was shown to be noticeably different between cells on CCMT and CoCrMo after 24 h in osteogenic culture, with cells on CCMT exhibiting greater spread with developed protrusions. Osteogenic differentiation was shown to be enhanced on CCMT compared to CoCrMo, with increased calcium ion content per cell (p < 0.05), greater hydroxyapatite nodule formation (p < 0.05) and reduced type I collagen deposition per cell (p < 0.05). The expression of the focal adhesion protein vinculin was shown to be marginally greater on CCMT compared to CoCrMo, whereas AFM results indicated that CCMT required more force to remove a single cell from the substrate surface compared to CoCrMo (p < 0.0001). These data suggest that CVD TiO2 coatings may have the potential to increase the biocompatibility of CoCrMo implantable devices.

Mechatronic feasibility of minimally invasive, atraumatic cochleostomy.

Robotic assistance in the context of lateral skull base surgery, particularly during cochlear implantation procedures, has been the subject of considerable research over the last decade. The use of robotics during these procedures has the potential to provide significant benefits to the patient by reducing invasiveness when gaining access to the cochlea, as well as reducing intracochlear trauma when performing a cochleostomy. Presented herein is preliminary work on the combination of two robotic systems for reducing invasiveness and trauma in cochlear implantation procedures. A robotic system for minimally invasive inner ear access was combined with a smart drilling tool for robust and safe cochleostomy; evaluation was completed on a single human cadaver specimen. Access to the middle ear was successfully achieved through the facial recess without damage to surrounding anatomical structures; cochleostomy was completed at the planned position with the endosteum remaining intact after drilling as confirmed by microscope evaluation.

Feasibility study of a hand guided robotic drill for cochleostomy.

The concept of a hand guided robotic drill has been inspired by an automated, arm supported robotic drill recently applied in clinical practice to produce cochleostomies without penetrating the endosteum ready for inserting cochlear electrodes. The smart tactile sensing scheme within the drill enables precise control of the state of interaction between tissues and tools in real-time. This paper reports development studies of the hand guided robotic drill where the same consistent outcomes, augmentation of surgeon control and skill, and similar reduction of induced disturbances on the hearing organ are achieved. The device operates with differing presentation of tissues resulting from variation in anatomy and demonstrates the ability to control or avoid penetration of tissue layers as required and to respond to intended rather than involuntary motion of the surgeon operator. The advantage of hand guided over an arm supported system is that it offers flexibility in adjusting the drilling trajectory. This can be important to initiate cutting on a hard convex tissue surface without slipping and then to proceed on the desired trajectory after cutting has commenced. The results for trials on phantoms show that drill unit compliance is an important factor in the design.

Small molecule stimulation enhances bone regeneration but not titanium implant osseointegration.

The osteogenic and osseointegrative potential of a small molecule was examined to assess its usefulness in regenerative procedures. Purmorphamine was used to stimulate bone growth and repair in an in vitro cell-based assay and an in vivo chick embryo CAM-assay with and without the presence of an implant. Purmorphamine adhered to precipitated hydroxyapatite coating, could activate the sonic hedgehog pathway and thereby stimulated osteodifferentiation. Porous calcium phosphate beads were used to deliver this small molecule in vivo and showed that purmorphamine increased the trabecular bone to bone area significantly. The assay showed purmorphamine failed to induce any significant difference in osseointegration on titanium coated PTFE implants. This suggests that, while a small molecule can enhance osteogenesis and might be useful in regenerative procedures, it failed to enhance the osseointegration of a Ti coated implant, suggesting that this sort of stimulation might be useful for enhancing bone regeneration where bone loss due to disease exists, but not for enhancing early stability of an implant.

The Control of Mesenchymal Stromal Cell Osteogenic Differentiation through Modified Surfaces.

Stem cells continue to receive widespread attention due to their potential to revolutionise treatments in the fields of both tissue engineering and regenerative medicine. Adult stem cells, specifically mesenchymal stromal cells (MSCs), play a vital role in the natural events surrounding bone healing and osseointegration through being stimulated to differentiate along their osteogenic lineage and in doing so, they form new cortical and trabecular bone tissue. Understanding how to control, manipulate, and enhance the intrinsic healing events modulated through osteogenic differentiation of MSCs by the use of modified surfaces and biomaterials could potentially advance the fields of both orthopaedics and dentistry. This could be by either using surface modification to generate greater implant stability and more rapid healing following implantation or the stimulation of MSCs ex vivo for reimplantation. This review aims to gather publications targeted at promoting, enhancing, and controlling the osteogenic differentiation of MSCs through biomaterials, nanotopographies, and modified surfaces for use in implant procedures.

Comparison on intracochlear disturbances between drilling a manual and robotic cochleostomy.

During cochlear implantation, hearing preservation is a concern. Minimizing disturbances to the cochlea and protection of the underlying endosteal membrane during the formation of a cochleostomy are considered important factors. The robotic micro-drill system tested in this article is the first example of an autonomous surgical drill successfully producing a cochleostomy, which keeps the underlying endosteal membrane intact. This study compares induced disturbances within the cochlea during formation of cochleostomy using the robotic micro-drill with that of conventional manual drilling. The disturbance of the endosteal membrane is measured using a Microscope Scanning Vibrometer at a third window, produced in the cochlea. Results show that the highest velocity amplitude measured was associated with manual drilling technique. The robotic micro-drill technique produced only about 1% of the peak velocity amplitude seen in manual drilling and exhibited much more uniform behaviour, while keeping the underlying membrane intact. The technique applied when using the robotic drill could be a major step in reducing the trauma to the cochlea, by reducing disturbance levels.

Robustness analysis of a smart surgical drill for cochleostomy.

BACKGROUND: There is a need for sensor-guided robotic devices that discriminate working conditions and media, and control interaction of tool-points with respect to tissues. At the micro-surgical scale the need is to control exact penetration through flexible tissues and to control relative motion with respect to moving or deforming tissue targets and interfaces. METHODS: This paper describes a smart surgical drill that is able to control interaction with respect to the flexing tissue to avoid penetration or to control the extent of protrusion with respect to the position of the flexible tissue interface under drilling. The sensing scheme used is able to discriminate between the variations in types of conditions posed in the drilling environment. RESULTS: The fully autonomous system is able to respond to tissue type, behaviour and deflection in real time. The system is robust in terms of different drilling angle, thickness, stiffness, and disturbances encountered. Also it is intuitive to use, efficient to set up and uses standard drill bits. CONCLUSIONS: The smart drill has been used to prepare cochleostomies in theatre and was used to remove bone tissue leaving the endosteal membrane intact. This has enabled preservation of sterility and the drilling debris to be removed prior to insertion of the electrode. Results presented in this paper suggest that the robotic smart drill is tolerant and robust on various angled drilling trajectories with respect to tissues, tissue thickness, environmental disturbances, and has been used within the operating theatre.

Hereditary gingival hyperplasia associated with amelogenesis imperfecta: a case report.

Hereditary gingival fibromatosis (HGF) and amelogenesis imperfecta (AI) are two rare oral conditions with genetic etiologies. The case of a 17-year-old boy affected by HGF, AI, anterior open bite, and pyramidal impaction of the maxillary molars is reported. Internal bevel gingivectomies were carried out to reduce gingival overgrowth. Clinical examination of the family revealed the presence of HGF and AI in his 12-year-old sister (both in milder forms) and of HGF in his older half brother. Genetic sequencing analyses were performed to detect any of the known mutations leading to HGF and AI. Histologic analysis revealed the presence of fibroepithelial hyperplasia, consistent with a diagnosis of GF. Sequencing genetic analysis failed to identify any of the common mutations leading to HGF (SOS-1) or AI (enamelin and amelogenin genes). This phenotype, similar to what has been described in other families, may represent a new syndrome caused by an as-yet unknown genotype.

Association between interleukin-6 polymorphisms and periodontitis in Indian non-smokers.

AIM: Genetic polymorphisms (SNPs) in the interleukin-6 (IL-6) gene have been associated with the presence of periodontitis. The aim of this study was to investigate the association between five SNPs in the IL-6 promoter region and the periodontal status of a rural Indian population. MATERIALS AND METHODS: Two hundred and fifty-one systemically healthy volunteers were clinically assessed by a single calibrated examiner and divided into: healthy individuals and periodontitis patients based on the European Workshop on Periodontitis definitions and on a recently suggested definition, which takes into account age and clinical attachment levels. Their genomic DNA was analysed blindly using real-time polymerase chain reaction to study IL-6 variants. The association between genetic factors and the presence of periodontitis was assessed by logistic regression. RESULTS: The IL-6-174 GG genotype was associated with periodontitis in non-smokers and older subjects (>45 years old). No statistically significant associations were detected between IL-6 haplotypes and periodontal status, after adjusting for confounders. CONCLUSIONS: The IL-6-174 polymorphism showed some evidence of an association with the periodontal status in non-smokers and older subjects in this rural Indian population. This association might be mediated by the effect of IL-6 on inflammatory responses.