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Biomedical subjects

Ashraf F Ayoub

Publications and source records attributed to Ashraf F Ayoub.

11 recordsLinked to original sources

One miniplate versus two in the management of mandibular angle fractures: a prospective randomised study.

We compared the use of one miniplate (n=36) with that of two miniplates (n=26) for the treatment of the mandibular angle in a randomised trial. There were no significant differences between the groups in total morbidity (22/36 compared with 14/26) or for individual complications. We conclude that two miniplates seem to confer no extra benefit to patients, but a much larger trial would be required to show this conclusively.

Adolescent↗

Ameloblastoma: a surgeon's dilemma.

PURPOSE: To investigate whether there were any significant differences in the mode of presentation, treatment, and outcome of patients presenting with a primary diagnosis of ameloblastoma in Glasgow, Scotland and San Francisco, CA. MATERIALS AND METHODS: All cases of ameloblastoma seen in both institutions between January 1, 1980 and December 31, 1999 were included in this study. Mode of presentation, radiographic appearance, histologic appearance, treatment, and follow-up were recorded. RESULTS: There were no significant differences in the clinical features on presentation (swelling, followed by pain, and altered sensation), the radiographic appearance (unilocular approximately 30% and multilocular 70%), or management with either local treatment (enucleation and/or curettage in just over 50% of cases) or radical treatment (a form of resection in under 50%) in the 50 cases included in this study. Primary care by conservative treatment led to a recurrence in approximately 80% of cases and this included cases of unicystic ameloblastoma. CONCLUSION: The mode of presentation, diagnosis, and management of the ameloblastoma was remarkably similar in Glasgow and San Francisco. The recurrence rate following local enucleation and curettage was unacceptably high, and this included the cases of unicystic ameloblastoma, which should be treated more aggressively than has been recommended in the past.

Adolescent↗

A new three-dimensional method of assessing facial volumetric changes after orthognathic treatment.

OBJECTIVE: To validate a new method of facial volumetric assessment that is dependent on the use of stereophotogrammetric models and a software-based Facial Analysis Tool. DESIGN: The method was validated in vitro with three-dimensional (3D) models of a lifelike plastic female dummy head and in vivo with a male-subject head. METHODS: Thirty facial silicone explants were added in the nasal and perioral regions of each head, and their volumes were obtained by three different algorithms. These were compared with the actual values obtained by a "water displacement" method. RESULTS: The least mean error was found with the "tetrahedron formation" method followed by the "projection" method and the "back-plane construction" method. The error with the tetrahedron formation method was 0.071 cm(3) (95% confidence interval [CI]: -0.074 to 0.2161 cm3) with the in vitro models and 0.314 cm3 (95% CI: -0.080 to 0.708 cm3) with the in vivo models. The increased volumetric assessment error observed in vivo was attributed to the registration procedure and possible changes in facial expression. CONCLUSIONS: These results encourage the use of this method in the 3D assessment of orthognathic surgical outcome, provided a standardized facial expression is used for image acquisition.

Algorithms↗

Early assessment of dental arch development in repaired unilateral cleft lip and unilateral cleft lip and palate versus controls.

OBJECTIVE: To evaluate dental arch relationships and dimensions, relative to an age matched noncleft sample, in Caucasian 3-year-old children with repaired unilateral cleft lip (UCL) or unilateral cleft lip and palate (UCLP). DESIGN: Prospective, cross-sectional, case-control study performed in Scotland, U.K. PARTICIPANTS: Eleven children with repaired unilateral cleft lip, 16 children with repaired unilateral cleft lip and palate, and 78 children as controls. MAIN OUTCOME MEASURES: Dental arch relationships and linear arch dimensions. RESULTS: Prevalence of Class III incisor relationship was 31.3% in children with unilateral cleft lip and palate compared with 9.1% in children with unilateral cleft lip. A buccal crossbite was present in 36% of children with unilateral cleft lip, compared with 75.6% of children with unilateral cleft lip and palate.Mean linear maxillary arch dimensions did not differ significantly between children with unilateral cleft lip and the controls. Except for second intermolar width, statistically significant differences existed in mean linear maxillary arch dimensions between the unilateral cleft lip and the unilateral cleft lip and palate groups; the mean linear maxillary arch dimensions were significantly greater in the control group than in the unilateral cleft lip and palate group. The mean cleft-affected anterior quadrant length appeared to be the arch dimension with the greatest power of discrimination among the three groups. There were no significant differences in mean linear mandibular arch dimensions among the three groups. CONCLUSIONS: Anterior crossbite was almost three times more common in the unilateral cleft lip and palate group than in the unilateral cleft lip group. Mean linear maxillary arch dimensions differed significantly between the unilateral cleft lip and palate group and the control group. There were no significant differences in mean linear maxillary arch dimensions between unilateral cleft lip and controls or between mean linear mandibular arch dimensions for unilateral cleft lip, unilateral cleft lip and palate, and controls.

Analysis of Variance↗

A minimally invasive novel design for a vascular-pedicled bone segment for experimental studies of reconstruction of mandibular defects.

We describe a new minimally invasive vascularised bone segment (VBS) for experimental reconstruction of the mandible. The study was validated and the feasibility was tested on fresh sheep cadavers. The integrity of the arterial blood supply was confirmed using inferior dental artery static arteriography. A pilot investigation was conducted on two adult sheep. Two full thickness bone cuts 35 mm apart were created in the parasymphyseal region. The inferior dental neurovascular bundle was preserved at the posterior bone cut but not anteriorly. A VBS was created, pedicled only on the inferior dental artery. The continuity of the mandible was maintained using fixation plates and the animals were followed up for 12 weeks. There was complete bony union and restoration of approximately 80% of the bony strength. The model is minimally invasive, reduces the operating time, and does not require special equipment and skills in microvascular anastomosis.

Animals↗

Three-dimensional assessment of facial soft-tissue asymmetry before and after orthognathic surgery.

We developed a new three-dimensional (3D) method of analysis of facial asymmetry and applied it to 44 patients: 20 Class III cases treated by bimaxillary osteotomy; 12 Class III cases treated by maxillary advancement alone, and 12 Class II cases treated by bimaxillary operations. 3D images were taken within a week before operation (T1), and one (T2), three (T3), and six (T4) months after operation. Landmarks were digitised on each 3D model and facial asymmetry scores were calculated. In the bimaxillary osteotomy group, facial symmetry improved after operation. In the maxillary advancement group, there was no notable improvement in facial symmetry after operation. In the bimaxillary group, facial symmetry deteriorated after operation, particularly at the tip of the nose and prominence of the chin. At six months follow-up, the changes in facial asymmetry in the three groups were not significant.

Adult↗

Three-dimensional facial characteristics of Caucasian infants without cleft and correlation with body measurements.

OBJECTIVE: The aim of this study was to characterize the soft tissue facial features of infants without cleft and to report on the correlation between these with weight, length, and head circumference. DESIGN: This was a prospective study using a noninvasive three-dimensional (3D) stereophotogrammetry (C3D) system to capture the images of the participants. Landmarks were identified on the 3D facial images. Means and SDs were derived for facial distances and angles. A facial asymmetry score was calculated for each image. Two sample Student's t tests, Pearson's correlation coefficients and analysis of covariance were used to ascertain any gender differences and determine whether these could be explained by weight differences. PARTICIPANTS: Eighty-three infants, 41 boys and 42 girls, were captured at rest with their lips apart, at approximately 3 months of age. RESULTS: Significant sex differences, of 1 to 2 mm, were found in several facial dimensions, such as face height and nose width. The larger facial measurements correlated significantly with body measurements. Analysis of variance confirmed these differences could be explained by differences in weight. There were no sex differences in the nose/mouth width ratios or in any of the angles measured, suggesting that there may be little sex difference in shape. A slight degree of asymmetry in the faces of infants without cleft was detected. CONCLUSIONS: Comparisons between noncleft controls and infants with cleft should take cognizance of normal age and sex variations in height and weight that occur among infants.

Age Factors↗

Comparative assessment of two methods used for interdental immobilization.

AIM: This investigation was carried out to compare Dimac wires with arch bars for interdental immobilization. MATERIAL AND METHODS: The assessment was conducted on 50 patients who had mandibular fractures and in whom intermaxillary fixation was required as a part of the treatment. The time required for applying each method of fixation, the needle-stick injuries that occurred during their application, and the periodontal damage that followed interdental immobilization was investigated. RESULTS: The mean time required for the application of Dimac wires was significantly less than that required for arch bars. The needle-stick injuries were significantly less with Dimac wires. Patients reported difficulty with oral hygiene with arch bars in place. This was associated with periodontal damage following removal of fixation. CONCLUSION: Dimac wires is safer to use and less traumatic to the periodontium

Fracture Fixation↗

Three-dimensional imaging in orthognathic surgery: the clinical application of a new method.

Many 3-dimensional (3D) techniques have been utilized to register and analyze the face in 3 dimensions, but each system has its own merits and disadvantages. C3D is a relatively new 3D imaging system that was developed to capture the 3D geometry of the face. Landmark identification on 3D facial models is facilitated by a software-based facial analysis tool developed by the authors. The reproducibility of landmark identification was high for 20 of the chosen points (standard deviations of repeated placements of landmarks around their centroids were 0.5 mm or less). The method is useful in studying facial soft tissue changes following orthognathic surgery and other types of facial surgery, as well as assessing facial soft tissue growth and development of the craniofacial complex.

Cephalometry↗