Biomedical subjects

Robert Sader

Publications and source records attributed to Robert Sader.

15 recordsLinked to original sources

PubMed2006

Three-dimensional versus two-dimensional sonography of the temporomandibular joint in comparison to MRI.

AIM: To compare clinical feasibility of static two-dimensional (2D) to three-dimensional (3D) sonography of the temporomandibular joint (TMJ) in assessment of disk dislocation and joint degeneration compared to magnetic resonance imaging (MRI). METHOD: Thirty-three patients, 66 TMJ were prospectively sonographed 2D and 3D (8-12.5MHz step motor scan), in occlusion and maximum opening with a probe position parallel inferior to the zygomatic arch. Axial 2D images were judged independent from the 3D scans; 3D volumes were cut axial, sagittal, frontal and rotated in real-time. Disk position and joint degeneration were assessed and compared to a subsequent MRI examination. RESULTS: The specific appearance of the disk was hypoechogenic overlying a hyperechogenic condyle in axial (2D) or sagittal and frontal (3D) viewing. Specificity of 2D sonography for disk dislocation was 63%, sensitivity 58%, accuracy 64%, positive predictive value 46%, negative predictive value 73%; for joint degeneration synonymously 59/68/61/38/83%. 3D sonography for disk displacement reached synonymously 68/60/69/51/76%, for joint degeneration 75/65/73/48/86%. 2D sonographic diagnoses of disk dislocation in the closed mouth position and of joint degeneration showed significantly different results from the expected values (MRI) in chi(2) testing; 3D diagnoses of disk dislocation in closed mouth position, of joint degeneration, 2D and 3D diagnoses in open mouth position were nonsignificant. CONCLUSIONS: Acceptable was the overall negative predictive value, as specificity and accuracy for joint degeneration in 3D. 3D appears superior diagnosing disk dislocation in closed mouth position as for overall joint degeneration. Sensitivity, accuracy and positive predictive value will have to ameliorate with future equipment of higher resolution in real-time 2D and 3D, if sonographic screening shall be clinically applied prior to MRI.

Adolescent↗

PubMed2006

3-D sonography for diagnosis of osteoarthrosis and disk degeneration of the temporomandibular joint, compared with MRI.

This study determined the value of three-dimensional (3-D) sonography for the assessment of osteoarthrosis and disk degeneration of the temporomandibular joint (TMJ). Sixty-eight patients (136 TMJ) with clinical dysfunction were examined by 272 sonographic 3-D scans. An 8- to 12.5-MHz motor-angulated transducer positioned inferior-parallel to the zygomatic arch scanned the region-of-interest. 3-D condylar morphology was compared with subsequent magnetic resonance imaging (MRI). Fifty-three datasets were complete, i.e., 106 TMJ, 212 examinations. 3-D sonographic examination took 5 min and attained 70% sensitivity/76% specificity/75% accuracy; positive predictive value was 44%%; negative predictive value was 90%. Disk degeneration was diagnosed synonymously with 64%/73%/71%/42%/ 87%. 3-D sonography proved to be reliable for exclusion of osteoarthrosis as disk degeneration compared with MRI, whereas the presence of osteoarthrosis and disk dislocation cannot be reliably diagnosed. Prospective use will include routine screening, using more sophisticated equipment with higher frequency in real-time 3-D viewing.

Adolescent↗

PubMed2006

3-D sonography for diagnosis of disk dislocation of the temporomandibular joint compared with MRI.

This study determines the value of three-dimensional (3-D) sonography for the assessment of disk dislocation of the temporomandibular joint (TMJ). Sixty-eight patients (i.e.,136 TMJ) with clinical dysfunction were examined by 272 sonographic 3-D scans. An 8- to 12.5-MHz transducer, angulated by step-motor, was used after picking a volume box on 2-D scan; magnetic resonance imaging followed immediately. Every TMJ was scrutinized in closed- and open-mouth position for normal or dislocated disk position. Fifty-three patients had complete data sets, i.e., 106 TMJ, 212 examinations. Sonographic examination took 5 min, with 74% specificity (62% closed-mouth; 85% open-mouth); sensitivity 53% (62/43%); accuracy 70% (62/77%); positive predictive value 49% (57/41%); and negative predictive value 77% (67/86%). This study encourages more research on the diagnostic capacity of 3-D TMJ sonography, with the advantage of multidimensional joint visualization. Although fair in specificity and negative predictive value, sensitivity and accuracy may ameliorate with future higher-sound frequency, real-time 3-D viewing and automated image analysis.

Adolescent↗

PubMed2006

The use of ozone in dentistry and maxillofacial surgery: a review.

Ozone has been successfully used in medicine because of its microbiologic properties for more than 100 years. Its bactericide, virucide, and fungicide effects are based on its strong oxidation effect with the formation of free radicals as well as its direct destruction of almost all microorganisms. In addition, ozone has a therapeutic effect that facilitates wound healing and improves the supply of blood. For medical purposes, ozone may be applied as a gas or dissolved in water. Despite the advantages that the therapeutic use of ozone offers, reservations remain in terms of its application in the oral and maxillofacial area. Particularly, the gaseous application of ozone is critically evaluated because of its possible side effects on the respiratory system. The objective of this article is to provide an overview of the current applications of ozone in dentistry and oral surgery. Research was based on peer-reviewed sources found through a Medline/PubMed search and other textbooks, reviews, and journals.

Anti-Infective Agents↗

PubMed2006

Piezoelectric harvesting of an autogenous bone graft from the zygomaticomaxillary region: case report.

The zygomaticomaxillary region offers a large amount of cortical bone that can be obtained simply and safely using the precise and selective cutting properties of a piezosurgical device. A block from this area fits nicely into anterior or premolar maxillary recipient sites and is thus the ideal choice, as no secondary surgical field is needed. As in conventional sinus bone graft procedures, the complication rate is minimal and after a 5-month healing period, the augmented region can be used for stable and esthetic oral implant placement.

Bone Transplantation↗

PubMed2005

Quantitative scanning acoustic microscopy compared to microradiography for assessment of new bone formation.

Recently, it has been shown that quantitative scanning acoustic microscopy (SAM) is a powerful tool to image the acoustic impedance of even inhomogeneous materials like bone. Therefore, the aim of our study was to compare SAM to conventional microradiography with respect to histomorphometrical assessment of undecalcified sections of newly formed bone. Forty specimens were harvested 12 weeks after implantation of either autogenous cancellous bone graft or 5.0 mg of Osteogenic Protein-1 (BMP-7) in a critical-sized defect model in sheep. Undecalcified transverse bone sections of 500 microm thickness were investigated with conventional microradiography and SAM. Linear regression analysis was carried out to compare the measurements of the area of new bone formation within the defect sites. Both methods allowed for good discrimination between newly formed bone and cortical bone at the edges of the former defect. Images obtained with SAM revealed a better resolution and sharpness compared to that of microradiographs since SAM imaging unlike microradiography does not depend on the thickness of bone sections. The results of quantitative histomorphometric analysis obtained by both methods showed no significant differences, and it was possible to predict 90% of the variability of each method (coefficient of determination r2 = 0.90; P < 0.0001). In conclusion, SAM offers comparable quantitative histomorphometric information with a better spatial resolution than conventional microradiography. Thus, SAM is a promising new micro-visualizing technique for basic bone research.

Animals↗

PubMed2005

Experimental and mathematical study of the influence of growth factors on the growth kinetics of adult human articular chondrocytes.

This study aimed at determining how kinetic parameters of adult human articular chondrocytes (AHAC) growth are modulated by the growth factor combination TGFbeta1, FGF-2, and PDGF BB (TFP), recently shown to stimulate AHAC proliferation. AHAC, isolated from cartilage biopsies of three individuals, were cultured in medium without (CTR) or with TFP. For growth curves, AHAC were seeded at 1,000 cells/cm(2) and cultured for 12 days, with cell numbers measured fluorimetrically in the same wells every 12 h. For microcolony tests, AHAC were seeded at 2.5 cells/cm(2) and cultured for 6 days, with cell numbers determined for each microcolony by phase contrast microscopy every 8 h. A mathematical model combining delay and logistic equations was developed to capture the growth kinetic parameters and to enable the description of the complete growth process of the cell culture. As compared to CTR medium, the presence of TFP increased the number of cells/well starting from the fifth day of culture, and a four-fold larger cell number was reached at confluency. For single microcolonies, TFP reduced the time for the first cell division by 26.6%, the time for subsequent cell divisions (generation time) by 16.8%, and the percentage of quiescent cells (Q(c)) by 42.5%. The mathematical model fitted well the experimental data of the growth kinetic. Finally, using both microcolony tests and the mathematical model, we determined that prolonged cell expansion induces an enrichment of AHAC with shorter first division time, but not of those with shorter generation time.

Aging↗

PubMed2005

In vivo animal trials with a scanning CO2 laser osteotome.

BACKGROUND AND OBJECTIVES: We report first results of animal trials using an improved laser osteotomy technique. This technique allows effective bone cutting without the usual thermal tissue damage. STUDY DESIGN/MATERIALS AND METHODS: A comparative in vivo study on mandibles of seven canines was done with a mechanical saw and a CO(2) laser based osteotome with a pulse duration of 80 microseconds. The laser incisions were performed in a multipass mode using a PC-controlled galvanic beam scanner and an assisting water spray. RESULTS: A complete healing through a whole bony rearrangement of the osteotomy gap with newly build lamellar Haversian bone was observed 22 days after the laser operations under optimal irradiation conditions. CONCLUSIONS: An effective CO(2) laser osteotomy without aggravating thermal side effects and healing delay is possible using the described irradiation technique. It allows an arbitrary cut geometry and may result in new advantageous bone surgery procedures.

Animals↗

PubMed2005

Intraoral piezosurgery: preliminary results of a new technique.

The piezosurgery instrument, developed in 1988, uses a modulated ultrasonic frequency that permits highly precise and safe cutting of hard tissue. Nerves, vessels, and soft tissue are not injured by the microvibrations (60 to 200 mm/sec), which are optimally adjusted to target only mineralized tissue. The selective and thermally harmless nature of the piezosurgery instrument results in a low bleeding tendency. In addition, the instrument can be used in operations requiring either local or general anesthesia. The precise nature of the instrument allows exact, clean, and smooth cut geometries during surgery. The difference in time requirement for surgical procedures using the piezosurgery instrument in comparison with the conventional drill is negligible. Postoperatively, excellent wound healing, with no nerve and soft tissue injuries, is observed. It is apparent that the range of application of piezosurgery is not limited to minor operations. Because of its highly selective and accurate nature, with its cutting effect exclusively targeting hard tissue, its use may be extended to more complex oral surgery cases, as well as to other interdisciplinary problems.

Adolescent↗

PubMed2005

Intraorbital abscess: a rare complication after maxillary molar extraction.

BACKGROUND: The orbit is prone to being affected by an odontogenous infection, owing to its anatomical proximity to the maxillary sinus. A possible reason for an ophthalmic manifestation of a dental abscess is extraction of an acutely inflamed tooth. CASE DESCRIPTION: The authors describe the treatment of a man who had painful swelling and redness in the area of his right eye after having a maxillary molar extracted a few days previous. A general dentist referred the patient to the clinic after he began to experience a progressive deterioration of vision of his right eye. Emergency surgical intervention prevented impending loss of vision, and subsequent healing was uneventful. CLINICAL IMPLICATIONS: To avoid serious complications, clinicians should not perform a tooth extraction when the patient is in the acute stage of a maxillary sinus infection. Appropriate diagnostic imaging and profound evaluation of the clinical state play major roles in managing the treatment of patients with inflammatory processes that involve the oral and paraoral regions.

Abscess↗

PubMed2004

Dynamic near-real-time magnetic resonance imaging for analyzing the velopharyngeal closure in comparison with videofluoroscopy.

PURPOSE: To demonstrate the feasibility of dynamic magnetic resonance imaging (MRI) with near-real-time temporal resolution ("real-time MRI") for analyzing the velopharyngeal closure in comparison with multiview videofluoroscopy. MATERIALS AND METHODS: Seven patients (three females and four males, 5-21 years old, mean age=11.3 years) with suspected velopharyngeal insufficiency, and one healthy volunteer were examined with videofluoroscopy and real-time MRI using a turbo-spin-echo (TSE) sequence (TR=170 msec, TE=21 msec, slice thickness=6 mm, six images per second). Imaging was done during phonation in all three image planes. The results were analyzed by two radiologists in comparison with videofluoroscopy as the standard of reference for overall image quality and the pattern of velopharyngeal closure. RESULTS: Real-time MRI correctly depicted the pattern of velopharyngeal closure in correspondence to videofluoroscopy in all cases. Concerning the movement of the pharyngeal walls, real-time MRI falsely depicted a general movement of the dorsal pharyngeal wall in one case, whereas videofluoroscopy showed no movement. In one patient, real-time MRI provided additional information by showing an asymmetric movement of the lateral pharyngeal walls that could not be depicted by videofluoroscopy due to technical limitations. Concerning image quality, the coronal plane was more difficult to evaluate with real-time MRI compared to videofluoroscopy. The axial plane was easier to analyze in real-time MRI compared to videofluoroscopy. CONCLUSION: Real-time MRI has the potential to depict the pattern of velopharyngeal closure in close correlation with videofluoroscopy, and may deliver additional information in selected cases.

Adolescent↗

PubMed2004

Consonant intelligibility and tongue motility in patients with partial glossectomy.

PURPOSE: The primary determinants for good speech outcome after glossectomy are not well established. This study evaluated the effect of tongue motility, type of reconstruction, and affected muscles on speech intelligibility. METHODS: Fourteen German glossectomy patients participated in an intelligibility test, which targeted lingual consonants. Tongue motility was rated on nine 3-point scales. Surgical mapping documented type of reconstruction and affected muscles. RESULTS: Mean consonant intelligibility was 71.25% and mean tongue motility was 34%. There was a moderate correlation between tongue motility and consonant intelligibility (r = 0.619). Patients with platysma flap reconstructions (n = 6) had a tendency for more correctly identified consonants. Patients with an intact genioglossus (n = 4) had significantly better tongue motility scores. CONCLUSIONS: The findings support the hypothesis that good tongue motility is a precursor of good postglossectomy speech. Although flap reconstructions led to better consonant intelligibility in this study, this should be interpreted with caution due to the small sample size.

Adult↗

PubMed2002

Three-dimensional craniofacial reconstruction imaging.

This review article aims to describe and discuss the imaging techniques most commonly used in medicine and dentistry to obtain three-dimensional images of the craniofacial complex. Three-dimensional imaging techniques provide extensive possibilities for the detailed and precise analysis of the whole craniofacial complex, for virtual (on-screen) simulation and real simulation of orthognathic surgery cases on biomodels before treatment, as well as for the detailed evaluation of the effects of treatment. Laser scanning in combination with the stereolithographic biomodeling seems to be a very promising combination for three-dimensional imaging, although there is still considerable room for improvement. Constant efforts should be made in the direction of developing and enhancing the existing techniques as well as exploring the potential for developing new methods based on emerging sectors of technology.

Cephalometry↗

PubMed2001

Levatorplasty, a new technique to treat hypernasality: anatomical investigations and preliminary clinical results.

Background: Velopharyngoplasty is the most commonly used operative technique for the treatment of velopharyngeal insufficiency. By attaching a posterior pharyngeal flap to the velum, a nonphysiological situation is created in the upper airway. Purpose: The aim of this investigation was to find a new surgical approach to physiological reconstruction of the velopharyngeal sphincter. Material: Anatomical investigations were performed in four cadavers. From this study a new surgical technique was developed and called 'levatorplasty': the musculus longus capitis was taken to create a new muscular loop leading to (a) an augmentation of the posterior wall, (b) a medial shift of the lateral pharyngeal wall; and (c) stretching of the velum posteriorly. Thus, the velopharyngeal space was reduced and a physiological closure of the nasal airway space could be obtained. Study design: The levatorplasty was employed in nine cleft palate patients with velopharyngeal insufficiency. Pre- and postoperatively the velopharyngeal closure was evaluated by phonetic and radiological examination. Results: The operation was easily performed without major complications. A concentric constriction with decrease of the velopharyngeal space was achieved and a definitive decrease of nasalance and hypernasality resulted. Conclusion: Long-term follow-ups have to verify whether these results will be stable. They also have to be compared with functional improvements following velopharyngoplasty or pharyngoplasty. Of special interest will be evaluation of the altered mobility of the lateral pharyngeal walls. Copyright 2001 European Association for Cranio-Maxillofacial Surgery.

Journal Article↗

PubMedDate not supplied

The influence of oral cavity tumour treatment on the voice quality and on fundamental frequency.

This study aimed to discover whether the surgical treatment of oral cavity tumours only affects on articulation or whether it also leads to a change in voice quality and fundamental frequency. Twelve participants were examined pre- and postoperatively for mean speaking fundamental frequency, standard deviation of the mean fundamental frequency, harmonic-to-noise-ratio and intrinsic pitch. All the parameters showed a substantial postoperative change in some patients.

Adult↗