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Biomedical subjects

H S Zaki

Publications and source records attributed to H S Zaki.

At least 19 recordsLinked to original sources
PubMed2004

Vanishing contrast enhancement in malignant glioma after corticosteroid treatment.

Malignant gliomas of the brain typically exhibit on CT or MRI a strong peripheral contrast enhancement area with a variable central zone of necrosis. These tumours are not known to change their radiological appearance and contrast enhancement pattern under systemic steroid treatment--a feature usually associated with primary CNS lymphoma. We report two cases of adult patients with glioblastoma multiforme and atypical hemispherical contrast enhancement initially demonstrated on MRI or CT, which disappeared after dexamethasone administration. At the same time, however, another tumour focus became visible, in both cases localised in the corpus callosum. Histological diagnosis was confirmed by stereotactic biopsy in both cases. This unusual changing pattern of contrast enhancement seems to be associated with multifocal malignant glioma with partial blood-brain barrier disruption modified by dexamethasone, and may present diagnostic difficulties in respect to neuroimaging and selection of target areas for tumour biopsy.

Administration, Oral↗
PubMed2001

Quantitative description of temporomandibular joint sounds: defining clicking, popping, egg shell crackling and footsteps on gravel.

This study presents a quantitative description of temporomandibular joint (TMJ) sounds provided by a rule-based classification system based on sound classification by three dentists, who listened to and classified the sound recordings as no sound, click, coarse crepitus and fine crepitus. The sounds were recorded with microphones in the ear canal from 126 subjects during vertical opening, digitized at 15 000 Hz, and replayed using a computer sound card and speakers. The dentists' classification of a test set resulted in intra- and inter-tester j values ranging from 0.71 to 0.81 and 0.61-0.73, respectively. Pooled j values for the dentists and the dentists plus the rules were 0.67 and 0.58, respectively, which were not significantly different in terms of the sound features on which the rules were based (P = 0.13). Linear discriminant analysis showed the four TMJ sound types were significantly different (P < 0.001). The performance of the rules was equivalent to the dentists and marginally better than the linear discriminant functions (P = 0.08), establishing the validity of the quantitative descriptions they provide. The recording and rebroadcast methodology produced sounds very similar to those observed in the clinic and could be used to train clinicians in classifying TMJ sounds.

Acoustics↗
PubMed2001

The association between research diagnostic criteria for temporomandibular disorder findings and biting force and endurance in patients with temporomandibular disorders.

OBJECTIVE: This study was designed to evaluate the association between examination findings based on Research Diagnostic Criteria for Temporomandibular Disorders and performances on bite force and endurance tasks. METHODS: Subjects were 126 patients with temporomandibular disorder and 34 pain-free controls. A subset of patients with temporomandibular disorder (n = 56) also were evaluated following a brief conservative 4-week treatment intervention. RESULTS: A multivariate analysis of variance indicated that female patients (P <.001) but not males (P =.17) had lower bite forces than age- and gender-matched controls. Dental examination findings were significantly but modestly predictive of bite task performance (R2 = 0.175), with higher joint pain and smaller maximum unassisted jaw opening associated with lower bite force. The brief treatment interventions resulted in both self-reported and clinically determined improvements. Clinical and self-reported improvement significantly predicted pre-post treatment changes in biting force among female subjects (R2 = 0.237). Specifically, reduction in joint palpation pain and self-reported pain (McGill Pain Questionnaire short form) were the primary predictors of increases in bite force. The improvement in biting force was modest (mean = 7 lb), and the force levels of female patients remained lower than those of control subjects. Treatment did not significantly increase endurance time. DISCUSSION: The brief conservative treatments used resulted in improvements in pain and jaw opening, and 81.8% of patients reported moderate to major improvement. The modest association of the bite task with Research Diagnostic Criteria for Temporomandibular Disorders examination findings and treatment improvement in this heterogeneous sample suggests that the bite and endurance tasks have limited diagnostic utility and sensitivity to treatment effects.

Journal Article↗
PubMed1999

The use of protective digit prostheses in management of microangiopathy of fingers.

Small artery occlusive disease (microangiopathy) of the palm and digital arteries may produce ischemia with painful ulcerations on the digits. These ulcerations may contribute to secondary infection and severe intolerance to thermal changes. The use of gauze wrappings to minimize ulceration has been tried; however, it is unhygienic and unsightly. A custom-made digit prosthesis is constructed with medical grade silicone over an artificial finger nail to provide positive seating of the prosthesis. The digit prosthesis is hygienic, esthetically acceptable to the patient and greatly protects ulcerated finger tips.

Arterial Occlusive Diseases↗
PubMed1999

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.

Acoustics↗
PubMed1998

A comparison of the effect of different occlusal forms in mandibular implant overdentures.

STATEMENT OF PROBLEM: Posterior tooth form selection for implant overdentures is made according to personal preference and experience using the concepts of conventional complete denture prosthodontics. PURPOSE: This study (1) compared the masticatory efficiency of three occlusal forms, 0 degrees, 30 degrees, and lingual contact (lingualized occlusion), in subjects with mandibular implant overdentures, and (2) determined their effects on the implant supporting tissues. MATERIAL AND METHODS: Eight patients who had four root form implants in the mandibular symphysis area connected with a Hader bar were selected. Maxillary and mandibular dentures were constructed for each patient with interchangeable posterior segments and the three occlusal forms were tested. The masticatory efficiency for each posterior tooth form was assessed with objective food tests and a subjective patient preference questionnaire. Periodic evaluation of implant-supporting tissues also was performed. RESULTS: Reliability analysis showed that all R1 coefficients were > or =0.80 (<0.001), indicating high subject consistency between multiple chewing efficiency trials. MANOVA analysis indicated a significant difference in chewing efficiency among the three occlusal forms (p < 0.001). The 0 degree occlusal form was associated with a significantly higher number of chewing strokes compared with 30 degrees or lingualized occlusal forms. The different occlusal forms were not found to have a clinically detrimental effect on the peri-implant soft or hard tissues. CONCLUSION: Chewing efficiency tests and patient preference ratings showed that 30 degree teeth and lingual contact provided better chewing efficiency than 0 degree teeth. None of the tested occlusal forms showed any clinical or radiographic detrimental effect on the implant-supporting tissues.

Aged↗
PubMed1997

A procedure for constructing dentures with interchangeable teeth.

Studies that compare different types of complete denture teeth have repeatedly emphasized the importance of standardizing all denture factors, except the type of teeth. Within-subject comparisons have also been recommended to avoid personal differences between patients. For optimum results, one denture should be constructed for each patient with interchangeable teeth. This article describes a simple and accurate procedure for constructing dentures with interchangeable posterior teeth.

Acrylic Resins↗
PubMed1997

Prosthetic management of large nasal septal defects.

Large nasal septal defect is defined as a defect that exceeds in size a stretched nostril. Large nasal septal defects cannot be closed by hard acrylic resin nasal septal obturators because of access and path-of-insertion problems. However, obturation can be achieved by construction of a nasal stent that fits into one of the nasal cavities. This article describes a procedure used to manage a large nasal septal defect with an intranasal heat-processed acrylic resin stent. The medial wall of the stent indirectly allows for the partition of the two nasal cavities. The stent is rendered patent to allow for comfortable breathing. The impression making and construction of these stents is not difficult. These nasal stents indirectly separate the two nasal cavities and effective obturation of large nasal septal defects is achieved.

Acrylic Resins↗
PubMed1996

Elongated styloid process in a temporomandibular disorder sample: prevalence and treatment outcome.

An elongated styloid process is an anatomic anomaly present in 2% to 30% of adults; it is occasionally associated with pain. Its prevalence among patients with classic temporomandibular disorder pain symptoms is unknown. The effect of conservative treatment on patients who have symptoms of temporomandibular disorders and an elongated styloid process is also unknown. The objectives of this study were to determine the prevalence of the elongated styloid process in a sample of patients with temporomandibular disorders and to compare patients with and without the elongated styloid process on initial presenting signs and symptoms and treatment outcome. A total of 100 panoramic radiographs of patients with symptomatic temporomandibular disorders were examined to ascertain the presence or absence of an elongated styloid process. All patients participated in a conservative treatment program of biofeedback and stress management and a flat-plane intraoral appliance. Initial symptoms and treatment outcome of patients with and without an elongated styloid process were compared by use of multivariate analysis of variance on several oral-paraoral and psychosocial-behavioral methods. The prevalence of an elongated styloid process in this clinic sample of temporomandibular disorders was 27%. The patients with or without an elongated styloid process were not significantly different in pretreatment symptoms, and both groups exhibited substantial treatment gains. However, patients with an elongated styloid process showed significantly less improvement on unassisted mandibular opening without pain than did patients who did not have an elongated styloid process. This suggests that an elongated styloid process may place structural limitations on pain-free maximum mandibular opening. The results support conservative management of patients with symptoms of temporomandibular disorders when an elongated styloid process is present.

Adolescent↗
PubMed1996

Dysfunctional patients with temporomandibular disorders: evaluating the efficacy of a tailored treatment protocol.

Forty-eight dysfunctional patients (i.e., high levels of pain, interference, and affective distress and low levels of perceived control) with temporomandibular disorders (TMDs) were randomly assigned either to a treatment consisting of an intraoral appliance (IA) and stress management with biofeedback (SM) plus nondirective, supportive counseling (SC) -- IA + SM + SC -- or to a customized treatment that included cognitive therapy (CT) with the IA and SM--IA + SM + CT. Both treatment groups reported statistically significant reductions on a set of physical, psychosocial, and behavioral measures posttreatment and at a 6-month follow-up. However, the intervention that included CT demonstrated significantly greater reductions in pain, depression, and medication use. Only the groups receiving the treatment that included the CT demonstrated continued improvements to the follow-up on pain associated with muscle palpation, self-reported pain severity, depression, and use of medications. These results support the efficacy of the tailored treatment for dysfunctional TMD.

Adult↗
PubMed1993

Effects of intraoral appliance and biofeedback/stress management alone and in combination in treating pain and depression in patients with temporomandibular disorders.

To assess the differential efficacy of two commonly used treatments for temporomandibular disorders (TMD), intraoral appliances (IAs) and biofeedback (BF), separately and in combination, two studies were conducted. The first study directly compared IA treatment, a combination of biofeedback and stress management (BF/SM), and a waiting list control group in a sample of 80 TMD patients. Both treatments were determined to be equally credible to patients, ruling out this potential threat to the validity of the results obtained. The results demonstrated that the IA treatment was more effective than the BF/SM treatment in reducing pain after treatment, but at a 6-month follow-up the IA group significantly relapsed, especially in depression, whereas the BF/SM maintained improvements on both pain and depression and continued to improve. The second study examined the combination of IA and BF/SM in a sample of 30 TMD patients. The results of this study demonstrated that the combined treatment approach was more effective than either of the single treatments alone, particularly in pain reduction, at the 6-month follow-up. These results support the importance of using both dental and psychologic treatments to successfully treat TMD patients if treatment gains are to be maintained.

Adolescent↗
PubMed1991

Three-dimensional finite element stress analysis in and around the Screw-Vent implant.

The three-dimensional finite element stress analysis method was used to determine the pattern and concentration of stresses within the Screw-Vent endosseous implant and its supporting tissues. For this commercially pure titanium implant, maximum stresses were located within the implant collar immediately below the bony crest. These stresses were at least 18 times less than the endurance limit of commercially pure titanium (259.90 MPa). Maximum stresses (19.57 MPa) in the bone were lingual to the superior portion of the collar. Previous longitudinal radiographic studies of a similar implant have revealed bone loss mesial and distal to the implant. For the Screw-Vent, mesial and distal stresses (maximum 0.38 MPa) were much lower than those buccal and lingual to the implant. The clinical significance of the stress transfer to the bone buccal and lingual to the implant has yet to be determined.

Alveolar Process↗
PubMed1990

Osseointegration in maxillofacial prosthetics.

Intra-oral and extra-oral prosthetic restorations of acquired and developmental defects (oral, para-oral, and facial) have had a fundamental problem of inadequate stability and retention of the prostheses. Application of osseointegration in maxillofacial prosthetic reconstruction followed the positive results obtained by using osseointegrated implants for retaining and supporting maxillary and mandibular dental prostheses. The two case presentations are illustrative examples of the clinical application of osseointegrated implants for maxillofacial reconstructive prosthetic procedures.

Dental Implantation, Endosseous↗