Vertical Protrusion Research Articles

The Relation of Maxillary Posterior Teeth Roots to the Maxillary Sinus Floor Using Panoramic and Computed Tomography Imaging in a Sample of Kurdish People

The relation of maxillary posterior teeth roots to the maxillary sinus floor is important for diagnosing and planning of many surgical procedures. In order to determine of this relation two imaging technique were used in this study.Paired panoramic radiographs and computed tomography images of maxilla from 27 subjects were taken and analyzed in the teaching hospitals of Sulaimani city during the period from Jan to Aug 2009. For both imaging modalities a total of 146 maxillary teeth were grouped according to their topographic relationship to the inferior border of the maxillary sinus followed Kwak et al. classification, were 0 indicated no contact between the root and inferior border of the maxillary sinus); 1 indicated that the root is in contact with the inferior border of the maxillary sinus; 2 indicated that the root is projecting laterally on the maxillary sinus cavity but its apex is outside the sinus boundaries; 3 and 4 indicated that the teeth roots that projected on the maxillary sinus cavity. Then roots were measured according to their projection lengths in the sinus cavity.Results of this study show that there was a high correlation between the two imaging technique for classification 0 and 1 relations. The OPG showed statistically significant (P>0.001) longer root projection in the sinus cavity in comparison with the root protrusion into the sinus measured by using CT images.As conclusion; for the majority of the roots projecting on the sinus cavity in panoramic radiographs, no vertical protrusion into the sinus was observed in CT images. Roots protrude into the sinus in the CT showed shorter projection length in comparison with panoramic radiography. Panoramic radiographs can provide adequate assessment about relation of the maxillary sinus floor. CT is indicated to provide the information about the relation to the maxillary sinus floor when there is protrusion detected in panoramic images.

Three-dimensional assessment of periodontal support of lower incisors for skeletal Class II malocclusion undergoing presurgical orthodontic treatment with different vertical skeletal patterns

BackgroundThe aim of the present study was to compare periodontal support changes during retraction of mandibular anterior teeth for skeletal Class II malocclusion with different facial divergence and to analyze relevant factors influencing bone remodeling by applying three-dimensional (3D) cone-beam computed tomography (CBCT) reconstruction technology.MethodsForty-eight patients with Class II malocclusion requiring surgical orthodontic treatment enrolled in the study were divided into the hyperdivergent group (n = 16), normodivergent group (n = 16) and hypodivergent group (n = 16) according to their vertical skeletal patterns. Cone-beam computed tomography (CBCT) scans were obtained before treatment (T1) and after presurgical orthodontic treatment (T2). The two-dimensional (2D) alveolar bone morphology, movement of mandibular central incisors and volume of the alveolar bone around incisors were measured on the labial and lingual sides by 3D CBCT reconstruction technology. Statistical analyses were performed with one-way ANOVA, paired t tests and multiple linear regression.ResultsDuring presurgical orthodontic treatment, the alveolar bone height on the labial side of the hyperdivergent group decreased significantly (P ≤ 0.05), but was maintained in the normodivergent and hypodivergent groups (P > 0.05). However, the alveolar bone volume, alveolar bone thickness at each level and alveolar bone height on the lingual side decreased significantly for all the groups. Apart from the initial morphometric measurements at T1, the morphology of lingual alveolar bone at T2 was significantly influenced by the direction and amount of tooth movement. Horizontal retraction and vertical protrusion of the root apex were negatively related to the alveolar bone on the lingual side after presurgical orthodontic treatment.ConclusionFor Class II malocclusion patients undergoing presurgical orthodontic treatment, the changes in the periodontal support of the lower central incisors varied in different vertical skeletal patterns. There exists a great periodontal risk of alveolar bone resorption on the lingual side for various vertical types. To avoid alveolar bone deterioration, it is essential to investigate the bone remodeling of patients with different alveolar bone conditions and cautiously plan tooth movement prior to orthodontic treatment. Moreover, 3D measurements based on CBCT construction can provide complementary information to traditional 2D measurements.

Correcting the Broad, Flat and Short Chin Using Modified M-genioplasty.

Several genioplasty techniques can narrow the width of the chin. Nevertheless, patients with a broad and short chin who received these methods were unsatisfied with the outcomes. The goal of this study was to analyze the clinical outcomes of modified M-shaped genioplasty for broad, flat and short chin deformity. Thirty-eight patients with broad, flat and short chins were included in this study from January 2019 to December 2021. The preoperative design was performed individually according to the data of the chin and the patient's desire of final chin shape. Narrowing and vertical elongating genioplasty was performed for all the patients with modified M-shaped genioplasty under general anesthesia according to the preoperative designs. All patients have completed the FACE-Q preoperatively and 3 months postoperatively. The results were evaluated by clinical appearances and FACE-Q scores. The vertical lengthening of the chin was 2-5mm, with an average of 3.02mm. The horizontal narrowing width was 3-6mm, with an average of 5.6mm. FACE-Q scores in satisfaction with the chin increased significantly from 35.34 ± 9.57 to 72.95 ± 6.81. There were no severe complications took place during the time frame of 3-24months postoperatively. The modified M-shaped genioplasty preserved the bone structure in the midsymphyseal area and suprahyoid muscular attachments as far as possible, and the bone segments may be repositioned quickly. This technique produced reliable and esthetically satisfying results in correcting a short, flat and broad chin, with altered vertical length, slope, width and protrusion three-dimensionally. This journal requires that authors assign a level of evidence to each article. For a full description of these Evidence-Based Medicine ratings, please refer to the Table of Contents or the online Instructions to Authors www.springer.com/00266 .

마스크와 모자 개발을 위한 20∼24세 남성의 얼굴 및 머리 유형 분석

This study attempted to analyze the face and head shape of 20∼24 aged males using the 8th Size Korea Survey and classify the types to find out the characteristics of each type. Through this, it was intended to provide data to help develop fashion items that span the face and head, such as masks and hats. A total of 39 items of data were analyzed with the SPSS 26.0 program. Among the measurement items on the face and head of men in 20∼24, the items with the largest standard deviation were Head Circumference, Bitragion Coronal Arc, Sagittal Arc of Head, Bitragion Cellion Arc, Bitragion Chin Arc, Menton to Occiput Length, etc. There are many items related to the vertical length of the face and head, indicating that men in 20∼24 have a large individual difference in the vertical length of the face and head. The face and head parts of 20∼24 aged males were classified into six categories: face and head vertical, face front width, face, and head thickness, eye spacing, under-eye vertical, and face protrusion. There were four types: short lower face & short face type, long lower face-flat face and thick head type, long-big face and flat head type, and wide-protruding face and thick head type. When developing a mask pattern, the mask

이론적 열유동 및 랜덤 진동 해석을 적용한 EPS 보냉용기의 포장설계

Although it has recently been regulated for use as an eco-friendly policy in Korea, the use of EPS (Expanded Polystyrene) cooling boxes, which are used as cold chain delivery insulation boxes for fresh agricultural and livestock products, is also increasing rapidly as e-commerce logistics such as delivery have increased rapidly due to COVID-19. Studies were conducted to optimize the EPS cooling container through internal air heat flow of CFD (Computational Fluid Dynamics) analysis and FEM (Finite Element Method) random vibration analysis using domestic PSD (Power Spectral Density) profile of the EPS cooling box to which the refrigerant is applied in this study. In the analysis of the internal air heat flow by the refrigerant in the EPS cooling box, the application of vertical protrusions inside was excellent in volume heat flow and internal air temperature distribution. In addition, as a result of random vibration analysis, the internal vertical protrusion gives the rigid effect of the cooling box, so that displacement and stress generation due to vibration during transport are smaller than that of a general cooling container without protrusion. By utilizing the resonance point (frequency) of the EPS cooling box derived by the Model analysis of ANSYS Software, it can be applied to the insulation and cushion packaging design of the EPS product line, which is widely used as insulation and cushion materials.

Single motor units from the medial pterygoid muscle can be active during isometric horizontal and vertical forces.

To determine (a) whether the medial pterygoid muscle is active in an isometric vertical force task and in isometric horizontal force tasks in the contralateral, protrusion and ipsilateral directions; (b) whether the same single motor units (SMUs) could be active across different directions of isometric force generation; and (c) whether different regions of the medial pterygoid muscle exhibit different patterns of SMU activation during the generation of any one direction of isometric force. Intramuscular electromyographic (EMG) recordings were made from the right medial pterygoid muscle in 15 healthy participants during isometric force tasks: vertical and horizontal contralateral, protrusion and ipsilateral. A computed tomography scan divided the EMG recording site into a medial or lateral part in each participant. Single motor units were discriminated in each task. Medial pterygoid SMU activity was recorded in 100% of participants for the vertical biting tasks, 86% of participants for the horizontal contralateral and horizontal protrusion tasks and 57% of the horizontal ipsilateral tasks. Of the 72 SMUs that were discriminated, 36% were active in all tasks; 18% were active only in the vertical tasks and 17% were active in the vertical, horizontal contralateral and horizontal protrusion tasks. The proportion of SMUs that was active in at least 1 horizontal task in the lateral part (33/39) was significantly higher than the proportion (21/33) in the medial part (Chi-Square, P<0.05). The data are consistent with a stabilisation role for the medial pterygoid muscle in isometric jaw forces in the vertical and horizontal planes.

Growth and Development of Craniofacial Structures in Patients at Different Ages With Unrepaired Submucous Cleft Palate

Submucous cleft palate (SMCP) is a particular subtype of cleft palate deformity; research related to the craniofacial features of patients with SMCP is comparatively rare. The study objective was to perform a cephalometric comparison of the craniofacial features of patients with SMCP and non-cleft controls at different ages. The sample in this cross-sectional study was composed of 2 groups: SMCP patients and non-cleft controls. The primary predictor variables were study group (cleft and non-cleft) and age. Age was divided into 3 groups. The outcome variables of interest were craniofacial measurements. The measurements used reflect cranial length, cranial angle, maxillary sagittal length and protrusion, maxillary vertical height, pharyngeal depth, facial height, mandibular length and protrusion, mandibular plane angle, and intermaxillary relation. Adjusted cephalometric craniofacial measurements between the groups were compared in 3 age groups using generalized linear models after being adjusted for age and gender. The study included 60 SMCP patients and 60 non-cleft controls.SMCP patients and non-cleft controls were divided into 3 subgroups: those aged 5 to 7years, those aged 9 to 11years, and those aged 18 to 30years. Patients with SMCP at age 5 to 7years showed a shortened cranial base length, maxillary sagittal length and height, and bony pharynx depth. Patients with SMCP at age 9 to 11years showed a smaller maxillary sagittal length and bony pharynx depth and an inharmonious jaw relationship. Patients with SMCP at age 18 to 30years showed a smaller maxillary sagittal length and height and an inharmonious jaw relationship. SMCP is associated with progressive maxillary retrognathism and reduced profile convexity from childhood to adulthood.

Electro-Active Polymer Based Soft Tactile Interface for Wearable Devices

This paper reports soft actuator based tactile stimulation interfaces applicable to wearable devices. The soft actuator is prepared by multi-layered accumulation of thin electro-active polymer (EAP) films. The multi-layered actuator is designed to produce electrically-induced convex protrusive deformation, which can be dynamically programmable for wide range of tactile stimuli. The maximum vertical protrusion is and the output force is up to 255 mN. The soft actuators are embedded into the fingertip part of a glove and front part of a forearm band, respectively. We have conducted two kinds of experiments with 15 subjects. Perceived magnitudes of actuator's protrusion and vibrotactile intensity were measured with frequency of 1 Hz and 191 Hz, respectively. Analysis of the user tests shows participants perceive variation of protrusion height at the finger pad and modulation of vibration intensity through the proposed soft actuator based tactile interface.

Correlation between maxillary sinus floor topography and relative root position of posterior teeth using Orthopantomograph and Digital Volumetric Tomography

Background: Maxillary sinus and its close proximity to the oral cavity make it a common clinical concern for medical and dental practitioners. Due to anatomical complexities, it is difficult to evaluate the relation between the root apices of maxillary posterior teeth and the floor of maxillary sinus which is essential for diagnosis of sinus pathology, understanding the path of dental infection and planning of dental treatment.Aims and Objectives: To correlate the topographic relationship of the maxillary sinus floor to the maxillary posterior teeth roots as imaged by pairs of Orthopantomograph (OPG) and Digital Volumetric Tomography images (DVT).Materials and Methods: A total of 510 maxillary teeth from 85 patients were classified according to their topographic relationship to the maxillary sinus and measured according to their projection lengths on the sinus cavity using OPG and DVT modalities.Results: In cases of classification 0, 85% and in classification 1 , 55.3% cases shows similar classification in both OPG and DVT. 28.5% of cases in both imaging modalities show classification 2. Only 15.9% of teeth roots exhibits classification 3. 11.1% of cases showed classification 4.The panoramic radiograph showed a statistically significant 2.24 times longer root projection on the sinus cavity in OPG comparison to DVT images.Conclusion: Teeth roots projecting in to the sinus in OPG, shows no vertical protrusion in to the sinus in DVT images. Hence DVT was better than OPG with measurements that were more exact and closer to anatomical reality.Asian Journal of Medical Sciences Vol.8(1) 2017 26-31

Windblown Dust Deposition Forecasting and Spread of Contamination around Mine Tailings.

Wind erosion, transport and deposition of windblown dust from anthropogenic sources, such as mine tailings impoundments, can have significant effects on the surrounding environment. The lack of vegetation and the vertical protrusion of the mine tailings above the neighboring terrain make the tailings susceptible to wind erosion. Modeling the erosion, transport and deposition of particulate matter from mine tailings is a challenge for many reasons, including heterogeneity of the soil surface, vegetative canopy coverage, dynamic meteorological conditions and topographic influences. In this work, a previously developed Deposition Forecasting Model (DFM) that is specifically designed to model the transport of particulate matter from mine tailings impoundments is verified using dust collection and topsoil measurements. The DFM is initialized using data from an operational Weather Research and Forecasting (WRF) model. The forecast deposition patterns are compared to dust collected by inverted-disc samplers and determined through gravimetric, chemical composition and lead isotopic analysis. The DFM is capable of predicting dust deposition patterns from the tailings impoundment to the surrounding area. The methodology and approach employed in this work can be generalized to other contaminated sites from which dust transport to the local environment can be assessed as a potential route for human exposure.

Spurious-free Lamb wave resonators with protrusion structures

In this letter, we demonstrate a technique to eliminate the spurious modes in aluminum nitride Lamb wave resonators (LWRs). The transverse acoustic wave characteristics are examined, and a resonance modulation theory on the regulation of mechanical boundary conditions is deducted. As examples of embodiments, vertical and lateral protrusion structures are proposed for the suppression. Finite element analysis verifies that the employment of these structures effectively restrains the transverse modes, and the measured electrical performance of the LWR with protrusions demonstrates an 11 dB reduction in the spurious response.

Effect of orbital protrusion and vertical interpalpebral distance on pterygium formation

To evaluate the risk factors in the development of pterygium in the Marmara region of Turkey as well as the efficacy of vertical interpalpebral distance, protrusion level and tear function in the development of pterygium. The cases were grouped in two as the research group consisted of patients with pterygium and the control group consisted of healthy people. A total of 294 patients with pterygium (108 bilateral, 186 unilateral) and 200 controls were included in the study. All patients and control group underwent a thorough ophthalmic examination, including tear function analysis using tear film breakup time measurement, protrusion level and vertical interpalpebral distance. No statistically significant difference was found between the bilateral pterygium subgroup and control group in terms of vertical interpalpebral distance and protrusion value (p=0.733, p=0.625). When the pterygium eyes and the control group were compared in the unilateral pterygium subgroup, no significant difference was found in terms of vertical interpalpebral distance and protrusion value (p=0.533, p=0.209). While UV efficiency in pterygium was obvious, protrusion value and vertical interpalpebral distance were not found to be a risk factor in the formation of pterygium.

The Parker Flex‐TipTM tube for nasotracheal intubation

We read with interest the recent article by Sanuki et al. [1]. Their results suggest that the Parker Flex-TipTM tube (Parker tube; Parker Medical, Highlands Ranch, CO, USA) appears to be beneficial for nasotracheal intubation due to a lower incidence of nasal mucosal trauma and postoperative nasal pain compared with a conventional tube. However, several design aspects of this article should be clarified. The authors did not clearly describe whether all tubes were oriented in a standard manner with the concavity of the tube facing infero-posteriorly on insertion. It is generally believed that epithelial stripping by the tube's tip and bevel, especially over the middle turbinate or nasal septum, is a common cause of epistaxis during nasotracheal intubation [2]. When a conventional tube with a left-sided bevel and a right tip orientation is inserted into the nasal passage, the turbinates are more at risk of damage in the right nostril whilst the septum is more at risk in the left nostril. When the Parker tube, with a posterior bevel and an anterior tip, is passed through the nasal cavity in a standard manner, its tip and bevel do not face or contend with the turbinates and septum in either nostril. Also, the soft and flexible tip of the Parker tube may centripetally collapse on impact. This may result in a larger surface area in contact with, and a lower overall pressure being exerted on, the nasal tissues, thus decreasing the nasal tissue dissection caused by the tube's tip and bevel. Epistaxis was assessed immediately after the tube's tip had passed into the pharynx. This might have led to an underestimation of the incidence of severe epistaxis because flow of blood from the damaged site into the pharynx is delayed by pressure exerted by a tube on the nasal passage. We feel that assessing the severity of epistaxis 5 min after nasotracheal intubation by a blinded investigator would obtain a more precise evaluation. Fifteen minutes after extubation, patients were asked to rate their nasal pain on a 100-mm visual analogue scale. At what stage did the independent anaesthetists explain the details of the visual analogue scale from 0–100 mm for each patient? It is unclear how the investigators would have avoided effects of residual anaesthesia on the assessment of early postoperative nasal pain. It would also have been useful to assess the differences between the two tubes in difficulty with nasal breathing, persistent nasal bleeding, and nasal pain on the first postoperative day. There is no available preformed nasal version of the Parker tube. During head and neck surgery, vertical protrusion of the Parker tube from the nostril may make surgical procedures more difficult. Compared with the preformed nasal tube, the Parker tube is more difficult to secure and lack of the distal curve does not allow the breathing system connection to be placed away from the surgical field without use of a special connector and may result in a high risk of the tube kinking leading to airway obstruction during surgery.

Is the intubating laryngeal mask tube really superior to the flexometallic tracheal tube for fibreoptic nasotracheal intubation?

We read with interest the recent article of Rai et al. [1], that concluded that the incidence of tracheal tube impingement during fibreoptic nasotracheal intubation is significantly lower with the intubating laryngeal mask (ILMA) tube than with the flexometallic tracheal tube. We believe it would be more appropriate to conclude that the ILMA tube is better only when the flexometallic tracheal tube is improperly orientated during passage. In this study, once the flexometallic tracheal tube was rotated anticlockwise by 90°, its success rate improved to 29 out of 30 patients, essentially the same as the success rate (30 out of 30) of the ILMA tube. It may be more appropriate always to start with the flexometallic tracheal tube orientated in a 90° anticlockwise direction. This technique has been used previously during awake fibreoptic orotracheal intubation, resulting in a higher success rate of intubation at the first attempt (100%) compared to the conventional approach (60%) [2]. Rotation of the bevelled tracheal tube randomly may reduce the difficulty in advancing a tracheal tube over a fibrescope, but 90° anticlockwise rotation should be effective in reducing impingement of the tracheal tube [3]. This manoeuvre was first suggested by Schwartz et al. [4]. Maktabi et al. [5] recommend 90° anticlockwise rotation as the first step to overcome difficulty in advancing the tracheal tube. Ho et al. [6] and Wheeler et al. [7] also suggested that the first attempt at railroading the tracheal tube should be done with the tracheal tube already turned in a 90° anticlockwise direction. In our practice, simple rotation of bevelled tracheal tubes anticlockwise by 90° during the first attempt has become a routine part of fibreoptic intubation [8]. This study by Rai et al. [1] should help popularise this. In the abstract, the authors conclude that compared to the ILMA tube, the incidence of laryngeal trauma from fibreoptic nasotracheal intubation may be significantly greater with the flexometallic tracheal tube, due to the higher incidence of glottic impingement. However, we find no evidence to support this in their results. This is concerning as in our experience, many readers do not read beyond the abstract of an article, and may then be misled by this statement. It may have been preferable to compare the two tubes for the severity of epistaxis, nasal pain, sore throat and dysphonia observed on the first post operative day. Both the flexometallic tracheal tube and ILMA tube lack a Ring-Adair-Elwin contour. For this reason, we feel that these tubes are not suitable choices for nasotracheal intubation for oral cavity and jaw surgery, as surgical access may be limited due to vertical protrusion of the tracheal tube from the nostrils. The absence of the distal curve of these tubes does not allow the breathing system to be positioned away from the surgical field without the use of an additional connector. The ILMA tube also requires a higher cuff pressure, which makes it less desirable, particularly in patients requiring nasotracheal intubation for a prolonged period.

Dynamics of magma flow near the vent: Implications for dome eruptions

Magma erupting out of a volcanic vent into a flow or a dome is subjected to a marked change of boundary conditions which strongly affects the distribution of gas pressure and stress within the flow. A numerical code is implemented to study the role of degassing-induced crystallization. The 2-D governing equations for a compressible viscous liquid are solved with a fully axially symmetric Finite Element Model for different crystal contents and vent geometrical shapes. The potential effects of gas pressure, deformation rates and elongational stresses on the stability of endogenous dome growth are studied for two shallow vent structures. For common eruption conditions, values of the internal gas pressure at the vent may be as large as 2 MPa. The magnitude of gas pressure at the vent is sensitive to the amount of crystallization and to the shape of the shallow conduit beneath the vent. High tensile stresses of ≈ 2 MPa are generated at the vent, which may account for ring fracturing of the dome and gas escape through shallow fissures. Such failure conditions may also lead to a change of exit conditions, from lateral spreading to the vertical protrusion of a lava spine.

Osteoarthritis of the temporomandibular joint: an evaluation of the effects and complications of corticosteroid injection compared with injection with sodium hyaluronate

The purpose of this study was to compare the efficacy and the complications of intra-articular temporomandibular joint (TMJ) injections in 40 patients with osteoarthritis of the TMJ. The subjects were randomly divided into two groups, and the patients received either two intra-articular injections with sodium hyaluronate or two intra-articular injections with corticosteroids, 14 days apart. The effect of the treatment was evaluated 14 days, 1 and 6 months after the initial injection and was based on the following measurements: pain intensity, pain localization, joint sounds, mandibular function and complications. Both groups of patients had less pain intensity at the 6-month follow-up, and there was significantly less pain intensity in the group of patients receiving sodium hyaluronate compared with corticosteroids (P = 0.001). A decrease in crepitation was seen in both groups. In the 20 subjects receiving sodium hyaluronate both the mandibular vertical opening and protrusion increased significantly (P < 0.000). Lateral movement from the affected side increased both in subjects injected with sodium hyaluronate (P = 0.024), and those injected with corticosteroids (P = 0.042). In conclusion, this study confirms that injections in the TMJ with sodium hyaluronate or corticosteroids may reduce pain and improve function in patients with osteoarthritis. The injections were more effective in patients with only TMJ pain compared with patients suffering from both TMJ and myofascial pain. Injection with sodium hyaluronate was significantly more effective in decreasing pain intensity than corticosteroids. Temporary pain after injections may be observed.

Gas sensing properties of printed multiwalled carbon nanotubes using the field emission effect

Gas sensors for NO 2 detection were fabricated using printed multiwalled carbon nanotubes (MWCNTs) before and after electric field surface treatment. Printed MWCNTs showed an increase of sensitivity upon exposure to NO 2 and field emission due to vertical alignment and protrusion of CNTs from surface layer after electric field surface treatment. Electron field emission plays a role recovery when exposed to gas molecules in CNT. A Fast recovery time of the printed MWCNT gas sensor was obtained by ohmic heat with a partial field emission effect at room temperature.

Correlation between maxillary sinus floor topography and related root position of posterior teeth using panoramic and cross-sectional computed tomography imaging

This study correlated the topographic relationship of the maxillary sinus floor to the roots of posterior teeth imaged by panoramic radiography and cross-sectional computed tomography (CT). Paired panoramic radiographs and CT images of maxillae from 80 subjects were analyzed. A total of 422 maxillary roots were classified according to their topographic relationship to the maxillary sinus and measured according to their projection lengths on the sinus cavity for both imaging modalities. Correlations between the 2 radiographic techniques were examined statistically. Teeth roots that did not contact the sinus floor or contacted it but did not project on the sinus cavity (classifications 0 and 1) showed a high agreement of 86% to 96% when using the 2 imaging techniques. Only 39% of the teeth roots that projected on the sinus cavity in panoramic radiographs (classification 3) showed protrusion into the sinus with CT. The panoramic radiographs showed a statistically significant 2.1 times longer root projection on the sinus cavity in comparison to the root protrusion length into the sinus measured by using CT images (P < .001). For the majority of the roots projecting on the sinus cavity in panoramic radiographs, no vertical protrusion into the sinus was observed in CT images. Roots that did protrude into the sinus in the CT showed a protrusion length that was much shorter than the projection length appearance using panoramic radiography.

The influence of mandibular movements on joint sounds in patients with temporomandibular disorders

Statement of problem. There are discrepancies among researchers concerning the reliability and use of temporomandibular joint sounds. Purpose. This study examined the reliability of mandibular movements and sounds and determined the correlation between movements and sounds. Material and methods. The mandibular movements of 35 subjects diagnosed with temporomandibular disorders were recorded with 2 CCD cameras, and sounds were recorded bilaterally with Panasonic electret condenser microphones in the ear canal. Subjects performed 3 movements, each repeated 5 times. Results. Reliability of maximum movements across the 5 trials was good to excellent, with Intraclass Correlation Coefficients (ICC) between 0.76 and 0.91 for all movements except protrusion. Temporomandibular sound event counts were reliable for most movements, including vertical opening, protrusion, and right and left laterotrusion (ICCs between 0.41 and 0.81). Most subjects produced sound events either in 100% or in none of the trials. Reliability for sound events was better during protrusion (ICCs between 0.56 and 0.81) than vertical opening (ICCs 0.41 to 0.64). Subjects with sound events during vertical opening (followed by closing) were significantly more likely to have sound events during protrusion (followed immediately by vertical opening and closing) ( P <.01). Conclusion. Temporomandibular sound events are generally reliable and warrant study regarding their use in classifying and diagnosing patients with temporomandibular disorders. Condylar translation, which occurs during both vertical opening and protrusion, appears to have a strong influence on the production of temporomandibular sound events. (J Prosthet Dent 1999;81:186-95.)

Enhanced convection from horizontal printed-circuit board with lifted electronic components

Convective heat transfer from the electronic component on a simulated horizontal printed-circuit board (PCB) assembly to the ambient air was found to be enhanced significantly by lifting the electronic components a vertical protrusion off from the board's surface. Effects of the gap between the lifted electronic component and the PCB's surface, the electronic component's pitch-to-height ratio and the Reynolds number of the air-flow on the heat dissipation from the PCB assembly were investigated experimentally. Heat transfer measurements were obtained for duct clearance-based Reynolds numbers from 400 to 19000. Enhanced convection was obtained by increasing the vertical protrusion of the lifted component, especially when the Reynolds number is high. When Reynolds number is lower than 2100, a maximum vertical protrusion of 6mm is recommended. Correlations for the prediction of the average heat transfer coefficient of the simulated horizontal PCB assembly by adopting the lifted electronic components were proposed.