|Year : 2018 | Volume
| Issue : 1 | Page : 40-43
A novel method of obtaining impression from three-dimensionally printed skull and incorporating medical grade silicone elastomer in fabricating silicone palatal feeding obturators for cleft lip and palate cases
Nafij Bin Jamayet1, Ahmed Mushfiqur Rahman1, Md Minhaz Ul Islam Nizami1, Wael Ahmed Bayomy Mohamed2, Mohammad Khursheed Alam3
1 Maxillofacial Prosthetics, Prosthodontic Unit, Universiti Sains Malaysia, Kota Bharu, Kelantan, Malaysia
2 Paediatric Unit, School of Dental Sciences, Universiti Sains Malaysia, Kota Bharu, Kelantan, Malaysia
3 Department of Orthodontic, College of Dentistry, Aljouf University, Sakaka, Saudi Arabia
|Date of Web Publication||26-Feb-2018|
Dr. Nafij Bin Jamayet
School of Dental Sciences, Health Campus, Universiti Sains Malaysia, Kubang Kerian, Kota Bharu 16150, Kelantan
Source of Support: None, Conflict of Interest: None
This report aims to depict a novel method in impression taking and feeding obturator fabrication for cleft lip and palate patients, utilizing three-dimensionally printed base of the skull from presurgical computerized tomography scan data. This technique uses soft and biocompatible medical grade room temperature vulcanizing silicone elastomer as the material of choice for fabrication procedure and reviews a representative patient case of a 10-month-old female child with bilateral cleft lip and palate deformity. Before final insertion, a strap was attached to the obturator as a safety precaution in case of accidental swallowing. The use of this unique technique satisfies all benefits of conventional feeding obturator with the added benefits of reducing most of its discomfort and difficulties of direct impression taking from the infant and fabricating process.
Keywords: Three-dimensional printing, cleft lip and palate, computed tomography–scan, feeding obturator, silicone
|How to cite this article:|
Jamayet NB, Rahman AM, Nizami MI, Mohamed WA, Alam MK. A novel method of obtaining impression from three-dimensionally printed skull and incorporating medical grade silicone elastomer in fabricating silicone palatal feeding obturators for cleft lip and palate cases. J Int Oral Health 2018;10:40-3
|How to cite this URL:|
Jamayet NB, Rahman AM, Nizami MI, Mohamed WA, Alam MK. A novel method of obtaining impression from three-dimensionally printed skull and incorporating medical grade silicone elastomer in fabricating silicone palatal feeding obturators for cleft lip and palate cases. J Int Oral Health [serial online] 2018 [cited 2022 Jan 18];10:40-3. Available from: https://www.jioh.org/text.asp?2018/10/1/40/226174
| Introduction|| |
Feeding obturator or nasoalveolar molding (NAM) is a prosthetic aid that is designed to obturate the cleft and restore the separation between the oral and nasal cavities. NAM facilitates in feeding, reduces nasal regurgitation, helps in the development of the jaws, and aids in speech, eliminating few of the many unfortunate difficulties of neonates and infants born with cleft lip and palate deformity.
However, a major concern with NAM is obtaining a good preliminary impression that leads to ill-fitting of the finished prosthesis. Furthermore, reluctance of infants wearing the obturator due to discomfort of the material and design of the prosthesis still remains., In an attempt to improve the fitting and reduce the discomfort level of the prostheses, a novel and a completely alternative approach has been taken in this case to fabricate a feeding palatal obturator for a 10-month-old child using the currently available silicone elastomer.
| Case Report|| |
The patient was a 10-month-old female child brought by her parents with a chief complaint of feeding difficulties and other complications associated with congenital bilateral cleft lip and palate deformity [Figure 1]a and [Figure 1]b. Intraoral examination showed missing primitive primary palate.
|Figure 1: Patient profile (a) frontal facial view, (b) intraoral view of the defect|
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- At first, a three-dimensional (3D) model of base of the skull of the patient was printed from her computerized tomography (CT) scan data [Figure 2]a. The patient was scanned using the Siemens Somatom Definition AS+ 128-slice (Siemens, Erlangen, Germany) at the Radiology Department, Hospital Universiti Sains Malaysia. The CT images were analyzed and processed using Mimics Software version 18 (Materialise NV, Belgium). The 3D model of the base of the skull was constructed to mimic the patient's base of the skull for designing the feeding obturator. The cropped virtual 3D model was later saved in stereolithography STL format, was sent to a 3D printer (Objet350 Connex, Stratasys, USA), and was then printed using transparent rigid Vero clear material (Stratasys, USA)
- Wax adaptation was done on the 3D-printed model using modeling wax (Tiranti, UK) mimicking the soft tissue in the mouth, and the nasal cavity was blocked using putty material to keep the minimum undercut necessary for retention of the silicone palatal obturator [Figure 2]a
- Impression was then taken with special tray made from self-cure acrylic resin (Fastray, Keystone Industries, NJ, USA) using light and regular body polyvinyl siloxane material (Chromaclone, Ultradent Products, Inc., South Jordan, Utah, USA) [Figure 2]b and [Figure 2]c. The special tray was constructed from the primary cast made from initial impression of the 3D-printed model
- Working cast was fabricated using type IV dental stone (Glastone, Dentsply Intl., USA) [Figure 3]a. Wax design was performed on the working cast for the pattern of the prosthesis [Figure 3]b
- After the wax design was complete, separating medium was applied on the working cast. Boxing wax was then adapted along the periphery of the working cast, and type IV dental stone was poured in it to fabricate a two-piece mold [Figure 3]c and [Figure 3]d
- Room temperature vulcanizing silicone A-2000 (Factor II Inc., Lakeside, AZ, USA) was dispensed according to the manufacturer's instructions in a mixing pad without adding any opacifier and pigments
- The mixed silicone was then packed into the upper and lower halves of the stone mold [Figure 3]d
- After complete polymerization, the two halves of the mold were separated and the prosthesis was detached from the mold
- The excess flash was trimmed and finished according to try-in on the working cast. Slight adjustments had to be done during final insertion of the prosthesis [Figure 4]a and [Figure 4]b
- Before the final insertion of the silicone palatal obturator, a strap was connected to the prosthesis as a safety precaution in case of accidental swallowing [Figure 4]c. This was only a precaution as the facial growth of the baby may interfere with fitting in the future. However, the parents reported that the adaptation of the prosthesis seemed very good not only at the moment but also after 2 weeks and 1 month follow-up.
|Figure 2: Impression taking (a) modification done on three-dimensional printed model using wax and putty material, (b) impression taking of the defect from three-dimensional printed model, (c) impression of the defect|
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|Figure 3: Wax design for prosthesis and Silicone loading (a) working cast, (b) wax design on working cast for prosthesis, (c) lower half of two-part mold, (d) silicone loading on upper half|
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|Figure 4: Final insertion (a) insertion of prosthesis, (b) final prosthesis in place, (c) incorporation of strap for safety precaution|
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| Discussion|| |
There have been numerous techniques documented over time to improve the fabrication process of feeding obturators. Unfortunately, none have successfully addressed the problems of the impression taking procedure. Preliminary impression taking becomes extremely challenging considering the age group of patients along with the impending risk of aspiration and swallowing of impression material. Clinicians have proposed specially designed impression tray, inverted posture of infants, and impression materials having various consistencies to ensure good detail duplication required for satisfactory fabrication of palatal prostheses.,, Despite all efforts, the agitation and nervousness of infants still remain a major factor that no technique has yet subdued.
However, use of CT scan and 3D-printed models in this current technique is a huge innovation in eliminating the above-mentioned problem. The presurgical evaluation CT scan for the corrective surgery has been utilized in this case to print a 3D model of base of the skull. The preliminary impression of the defect has been taken from this model after certain wax adaptation, thus avoiding the direct impression taking of the uncooperative infants. This completely alternative impression taking allows minute details to be reproduced including the valuable undercuts in minimum time so important for retention of the obturator and saves ample time of the clinician and parents compared to conventional and slightly modified impression techniques.,,
Another vital difference in this fabricating technique is the use of silicone materials. Conventionally, acrylic has been the material of choice in spite of its chance of irritating the oral mucosal or gingival tissue. The molding plate of the obturator needs to be relieved in all areas that exerts excessive pressure.,, All such risks can be avoided with the use of silicone with its soft consistency and excellent biocompatibility. Moreover, all modifications needed to be done on the prosthesis can be performed in the laboratory and tried in the printed model, thus sparing the repeated visits to the clinic. After all adjustments, the patient is called in for the final insertion of the finished palatal obturator.
The unique impression technique used in this case is not only accurate in producing minute details of the defect that is highly difficult from direct impression in infants but also less risky and time-consuming considering the fact of aspiration of impression materials, for which additional safety team and oxygen support are needed. The use of medical grade silicone for actual fabrication of obturator makes the prosthesis even more effective as it overcomes the oral mucosal irritation and excessive pressure of conventionally used materials.,,
This technique would be more rapid if 3D printer could have been used for printing of the prosthesis as well. Unfortunately, this is not possible yet as the current materials available for 3D printing are not as biocompatible and soft as silicone materials. Even if such materials were available that would have required specialist in craniofacial morphology and software engineering to design and formulate the impression tray, mold, or the prosthesis itself., However, this method does not need such technical support. Only CT scan data are required to print the 3D base of the skull from a 3D printer either present in the same hospital or any nearby institution.
Despite these techniques' many advantages, it poses one difficulty. The 3D model printed from the CT scan data represents only hard tissues. However, the prosthesis will be inserted on soft tissues overlying hard tissues in the mouth. In effort to overcome this problem, threshold level of CT scan data saved in digital imaging and communication in medicine file format was enhanced which gave a minimum image of the soft tissue, and wax adaptation was done on 3D-printed base of the skull to simulate soft tissues adding an extra step in the fabricating process.
Despite the aforementioned modifications performed on this case to mimic the surrounding soft tissues of the mouth, it was not possible to achieve an exact simulation of the soft tissues. Therefore, there could have been issues regarding inadequate retention and disproportionate pressure on the fitting surface. However, accurate wax adaptation minimized the effect and a satisfactory retentive palatal feeding obturator was achieved. Even though a satisfactory palatal feeding obturator was fabricated, researches should be done to eliminate this soft tissue problem. The feeding obturator would be much more accurate and beneficial if the soft tissue information can be incorporated during the analysis and processing of the CT images in the Mimics software. The integration of the soft tissue thickness with the hard tissue information of the CT image would mean a 3D-printed model with a combined thickness of soft and hard tissue of the mouth, thus leading to the elimination of the wax adaptation stage and fabrication of an accurate and most retentive feeding obturator in the future.
| Conclusion|| |
This article describes an entirely novel and alternative method for impression taking and fabrication of feeding obturators for cleft lip and palate patients. The use of this unique technique satisfies all the benefits of a conventional feeding obturator with the added benefits of reducing most of its usage discomfort and difficulties of impression and fabricating process.
This case study has been supported by Universiti Sains Malaysia (USM) short-term grant no: 304/PPSG/61313144.
Declaration of patient consent
The authors certify that they have obtained all appropriate patient consent forms. In the form, the patient's parents have given their consent for her images and other clinical information to be reported in the journal. The patient's parents understand that name and initials will not be published and due efforts will be made to conceal identity, but anonymity cannot be guaranteed.
Financial support and sponsorship
Conflicts of interest
There are no conflicts of interest.
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