Zainul Ahmad Rajion

Tooth size and dental arch dimensions: a stereophotogrammetric study in Southeast Asian Malays

OBJECTIVE To investigate tooth size and dental arch dimensions in Malays using a stereophotogrammetric system. SETTING AND SAMPLE POPULATION The sample consisted of 252 subjects with ages ranged from 13 to 30 years. MATERIALS AND METHODS Images of dental casts were captured by stereophotogrammetry and selected variables were measured using a three-dimensional (3D) imaging system. Sex differences and changes associated with age were assessed, and interrelationships between different variables were explored within the study group. RESULTS Men had significantly larger mesio-distal crown widths and dental arch dimensions than women (p < 0.05). None of the dental arch dimensions or mesio-distal crown widths showed a significant change because of age except the widths of the upper canine, lower first molar and central incisor. Significant correlations of tooth size with dental arch dimensions were found, particularly with arch lengths and perimeters. A principal component analysis showed interrelationships between the majority of tooth size variables with inter-canine width, arch length and perimeter distances. CONCLUSION This study has established new reference data for tooth size and arch dimensions in Malays and demonstrated patterns of variation that are relevant to anthropologists interested in making comparisons within and between different populations and also to clinicians developing treatment plans for their patients. The study confirmed the accuracy of the 3D photogrammetric method for measuring dental casts.

A three-dimensional computed tomographic analysis of the cervical spine in unoperated infants with cleft lip and palate

Objective: To investigate anatomical variations and abnormalities of cervical spine morphology in unoperated infants with cleft lip and palate. Design: Retrospective cross-sectional investigation of infants born with nonsyndromic cleft lip and palate using computed tomography scans acquired for investigation of a spectrum of clinical conditions. Setting: Computed tomography scan data were obtained from 29 unoperated cleft lip and palate infants and 12 noncleft infants of Malay origin, ages 0 to 12 months. Methods: Observational study of cervical spine computed tomography scans. Heights of cervical vertebral bodies (C2-C7) and intervertebral spaces were measured from landmarks identified from computed tomography reformats and three-dimensional computed tomography reconstructions. Linear modeling of heights and spaces, with age as a covariate, was undertaken to identify differences between the samples. Results: Anomalous features observed in the cleft lip and palate sample included short posterior arch of C1 (2/29), abnormal development of the anterior arch of C1 (2/29), and fusions of the posterior arch of C2 and C3 (2/29). No anomalies of the cervical spine were observed in the noncleft sample. Although the heights of three cervical vertebral bodies were significantly smaller and two intervertebral spaces were significantly larger in infants with cleft lip and palate compared with noncleft infants (p < .05), overall length of the cervical spine did not differ significantly between the samples. Conclusion: There was evidence for subtle upper spinal anomalies in the infant cleft lip and palate population. Our finding of reduced size of some cervical vertebral bodies may reflect delayed upper spinal development in infants with cleft lip and palate.

Optimizing supercritical carbon dioxide in the inactivation of bacteria in clinical solid waste by using response surface methodology

Clinical solid waste (CSW) poses a challenge to health care facilities because of the presence of pathogenic microorganisms, leading to concerns in the effective sterilization of the CSW for safe handling and elimination of infectious disease transmission. In the present study, supercritical carbon dioxide (SC-CO2) was applied to inactivate gram-positive Staphylococcus aureus, Enterococcus faecalis, Bacillus subtilis, and gram-negative Escherichia coli in CSW. The effects of SC-CO2 sterilization parameters such as pressure, temperature, and time were investigated and optimized by response surface methodology (RSM). Results showed that the data were adequately fitted into the second-order polynomial model. The linear quadratic terms and interaction between pressure and temperature had significant effects on the inactivation of S. aureus, E. coli, E. faecalis, and B. subtilis in CSW. Optimum conditions for the complete inactivation of bacteria within the experimental range of the studied variables were 20 MPa, 60 °C, and 60 min. The SC-CO2-treated bacterial cells, observed under a scanning electron microscope, showed morphological changes, including cell breakage and dislodged cell walls, which could have caused the inactivation. This espouses the inference that SC-CO2 exerts strong inactivating effects on the bacteria present in CSW, and has the potential to be used in CSW management for the safe handling and recycling-reuse of CSW materials.

Preparation and characterization of a newly developed polyamide composite utilising an affordable 3D printer

In this work, the potential of polyamide composite prepared by a 3D printer was evaluated. Polyamide 12 was compounded with 5 wt% hydroxyapatite and 15 wt% zirconium oxide fillers via a twin screw extruder. The compound was then pelletized prior to the preparation of the filament by a desktop filament extruder. The filament was finally applied to a 3D printer to prepare the printed tensile samples. Pure polyamide 12 and commercial polyamide filament, Taulman 618, were also printed and tested for control. Melt flow and thermal analysis were carried out to estimate the processing conditions. Tensile test was also conducted to evaluate the strength and modulus. The new polyamide composite was successfully prepared and tested. The strength of polyamide composite was comparable to Taulman 618. The modulus of the composite was improved due to the incorporation of fillers. The morphology of the printed composite was porous, which could provide pros and cons to biological and mechanical properties, respectively. Polyamide composite presented a promising polymer material for a 3D printer and may be applied for biomaterial application.

The hyoid bone in Malay infants with cleft lip and palate

Objective: To compare morphological and positional variations of the hyoid bone in unoperated infants with cleft lip and palate (CL/P) with those in noncleft infants. Design: Retrospective, cross sectional. Patients and Methods: Three-dimensional computed tomography scans were obtained from 29 unoperated CL/P infants of Malay origin aged between 0 and 12 months and from 12 noncleft infants in the same age range. Observations were made and measurements were obtained with a software package developed at the Australian Craniofacial Unit. The sizes of the hyoid bones and the position of the hyoid body and epiglottis in relation to the cervical spine were measured. Anatomical anomalies of the hyoid and prevalence of aspiration pneumonia were also documented. Results: The hyoid bones and epiglottis were found to be located more inferiorly in CL/P infants compared with the noncleft infants. Also, 17% (5/29) of the CL/P infants had nonossified hyoid bodies. Conclusion: The results suggest that there are differences in the location and genesis of the hyoid bone in infants with CL/P that warrant further investigation.

3D CT Imaging for Craniofacial Analysis Based on Anatomical Regions

The development of a craniofacial database is a multidisciplinary initiative that will provide an important reference for community, security, social and medical applications. A method of landmark identifications and measurements in 3D on craniofacial patients is described. Anatomical regions such as mandible, orbits, zygoma and maxilla are located, created and stored as templates of 3D CAD files for subsequent analysis. Data from these images were tested for accuracy and repeatability by comparing with direct measurements using caliper and CMM. The landmark points are reproducible in CAD system for further analysis. It was found that the approach provides a fast, accurate and efficient method for landmarks identification of the craniofacial areas in database development

Coordinate Systems Integration for Development of Malaysian Craniofacial Database

This study presents a data registration method for craniofacial spatial data of different modalities. The data consists of three dimensional (3D) vector and raster data models. The data is stored in object relational database. The data capture devices are laser scanner, CT (computed tomography) scan and CR (close range) photogrammetry. The objective of the registration is to transform the data from various coordinate systems into a single 3-D Cartesian coordinate system. The standard error of the registration obtained from multimodal imaging devices using 3D affine transformation is in the ranged of 1-2 mm. This study is a step forward for storing the spatial craniofacial data in one reference system in database

New Approach to 3D Printing of Facial Prostheses Using Combination of Open Source Software and Conventional Techniques: A Case Report

The wax sculpting of a maxillofacial prosthesis is challenging, time-consuming, and requires great skill. Rapid prototyping (RP) systems allow these hurdles to be overcome by enabling the creation of a customized 3D model of the desired prosthesis. Geomagic and Mimics are the most suitable software programs with which to design such prostheses. However, due to the high cost of these applications and the special training required to operate them, they are not widely used. Additionally, ill-fitting margins and other discrepancies in the final finished products of RP systems are also inevitable. Therefore, this process makes further treatment planning difficult for the maxillofacial prosthodontist. Here, we report the case of a 62-year-old woman who attended our clinic. Initially, she had presented with a right facial defect. This was later diagnosed as a squamous cell carcinoma and resected. The aim of this report is to describe a new technique for the 3D printing of facial prostheses which involves the combined use of open-source software, an RP system, and conventional methods of fabrication. The 3D design obtained was used to fabricate a maxillofacial prosthesis to restore the defect. The patient was happy with the esthetic outcome. This approach is relatively easy and cheap, does not require a high degree of non-medical training, and is beneficial in terms of clinical outcome.

NURBS curves with the application of multiple bones fracture reconstruction

Abstract The challenging task of treating trauma to cranio-maxillofacial requires advanced radiological imaging and high clinical skills. The reconstruction of facial fractures focuses on the rehabilitation of patients functionally as well as in aesthetics. In this article we used NURBS curves to construct the multiple bones fracture using CT scan data in Digital Imaging and Communications in Medicine (DICOM) format. The reconstruction process of multiple bones fracture start with the boundary extraction followed by corner detection, optimization of knots, weights, construction of fractured part inner outer curve for each CT scan slice using NURBS curves and finally the construction of fractured part in DICOM format. The construction process using proposed method is based on DICOM data only that does not require any technique such as technical help, mirror imaging, to take average thickness of skull bone or reference skull, etc. The constructed fractured implant is custom made for each patient. We present a real case in which multiple bones fracture has been constructed using NURBS curves. The proposed method has also been validated quantitatively and qualitatively using self supposed fractured data.

A Hybrid Selection Method Based on HCELFS and SVM for the Diagnosis of Oral Cancer Staging

A diagnostic model based on Support Vector Machines (SVM) with a proposed hybrid feature selection method is developed to diagnose the stage of oral cancer in patients. The hybrid feature selection method, named Hybrid Correlation Evaluator and Linear Forward Selection (HCELFS), combines the advantages of filters and wrappers to select the optimal feature subset from the original feature set. In HCELFS, Correlation Attribute Evaluator acts as filters to remove redundant features and Linear Forward Selection with SVM acts as the wrappers to select the ideal feature subset from the remaining features. This study conducted experiments in WEKA with ten fold cross validation. The experimental results with oral cancer data sets demonstrate that our proposed model has a better performance than well-known feature selection algorithms.