According to the International Perinatal Database of Typical Orofacial Clefts, the prevalence of cleft lip and palate (CLP) amounts to 9.92 per 10,000 live births worldwide,1 making it the most common facial birth defect. Despite the relevance of this global health issue, the knowledge level on CLP is alarmingly low. This refers not only to the general population but also to medical professionals of all training stages. Investigations among medical and dental students as well as among trainees and physicians of disciplines other than ENT and craniomaxillofacial surgery have shown glaring gaps in the knowledge on CLP.2,3 In contrast, willingness to learn about patients with CLP is huge in developing and industrial countries.4 Medical therapy of patients with CLP in their first weeks of life represents a key step toward achieving a normal development in speaking, swallowing, and drinking as well as a normal visual appearance.5 These facts underline the significance of developing useful teaching methods for an effective illustration of this essential topic. Our aim was to construct a realistic haptic anatomic CLP model that can be used for 3-dimensional visualizing CLP and practicing the first steps of CLP treatment. We furthermore intended to evaluate the didactic benefit of using the CLP model in a teaching course for medical students.
Models of newborns with CLP are not commercially available so far. Therefore, construction was based on a purchased model of a healthy newborn. To construct a close-to-reality model, we searched for a baby doll, being in accordance with a real baby in size and body proportion. Decision was made in favor of baby doll BA75 (Figure Ia, https://links.lww.com/SIH/A176 Supplemental Digital Content 1) by “AKSE” (online direct mail for anatomic models), which satisfied our demands in terms of anatomic shape—well-formed head and wide-open mouth—and reasonable costs (€54). The baby doll is made out of polyvinyl chloride–based plastics, has a length of 48 cm, and weighs 1650 g. The production steps of the CLP model are described in detail in the “Results” section.
Integration of the CLP Model Into a Teaching Course
In our medical school, a practical training day for oral and maxillofacial surgery is performed once a semester for medical students of advanced semester. Participation in the course was mandatory for each student. The course begins with a short multiple-choice test to survey previous knowledge in oral and maxillofacial surgery. The multiple-choice test was on a voluntary basis. After the test, the students are given short lectures on the 3 other topics besides CLP: trauma, microsurgery, and reconstructive surgery. After completing the test, the students are divided into groups of up to 5 for rotating between 4 hands-on stations. At the end of the training day, the multiple-choice test is repeated. Because of anonymity, students are told to use a pseudonym for both questionnaires. We added CLP as a fourth theme complex to this existing teaching concept. In the CLP hands-on station, students were given the tasks of (1) taking an intraoral impression with alginate impression material, (2) positioning of a drinking plate in the oral cavity, and (3) fixating a nasoalveolar molding plate with extraoral tapes. Before the students started to interact with the CLP model, all essential steps and facts were first demonstrated. Preteaching and postteaching scores of the multiple-choice tests were analyzed, and the results for each student were compared. Statistical analyses were performed using SPSS 20.0 (SPSS, Inc, Chicago, IL). Significances were calculated by using the t test of paired samples. The level of significance was set at P < 0.05.
Production of the Haptic CLP Model
The first work step in fabricating the CLP model was to define the dimensions of a complete unilateral CLP in the baby doll’s face by marking the areas, which were to be excised in the lip and subnasal region (Figure Ib, https://links.lww.com/SIH/A177 Supplemental Digital Content 2) and in the palate (Figure Ic, https://links.lww.com/SIH/A178 Supplemental Digital Content 3). A suitable patient’s plaster model from our archive served as a template. After cutting out the tagged areas either with a scalpel (Figure IIa, https://links.lww.com/SIH/A179 Supplemental Digital Content 4) or a soldering iron (Figure IIb, https://links.lww.com/SIH/A180 Supplemental Digital Content 5), edges were rounded off by using a handheld rotating milling machine (Figure IIc, https://links.lww.com/SIH/A181 Supplemental Digital Content 6). A rounded slice of plastic in size of a €2 coin was cut out from the inner side of the doll’s thigh (Figure IIIa, https://links.lww.com/SIH/A182 Supplemental Digital Content 7). Then, the cleft side ala of the nose was milled out completely and reshaped in the form of a typical flattened nose wing by melding on the plastic slice (Figure IIIb, https://links.lww.com/SIH/A183 Supplemental Digital Content 8). The doll’s hard and soft palate was milled out completely (Figure IVa, https://links.lww.com/SIH/A184 Supplemental Digital Content 9). A cast of a patient with a cleft palate (Figure IVb, https://links.lww.com/SIH/A185 Supplemental Digital Content 10) was milled to fit into the oral cavity of the baby doll. The head of the baby doll was removed temporarily to position the cast from inside the head. By use of a delicate iron rod (Figure IVc, https://links.lww.com/SIH/A186 Supplemental Digital Content 11), the cast was then fixated inside the doll’s head (Figure IVd, https://links.lww.com/SIH/A187 Supplemental Digital Content 12). Remaining residues of burned plastic material were stripped off with the milling machine using different collets (Figure Va, https://links.lww.com/SIH/A188 Supplemental Digital Content 13), and skin-colored lacquer and cosmetic products were applied to adapt the skin color (Figure Vb, https://links.lww.com/SIH/A189 Supplemental Digital Content 14) for the final shape (Figure Vc, https://links.lww.com/SIH/A190 Supplemental Digital Content 15). The final CLP model is demonstrated in Figure 1. A list of all instruments and materials used in the production of the CLP model is provided as Supplementary Digital Content (Figure VIa, https://links.lww.com/SIH/A191 Supplemental Digital Content 16) (Table VIb, https://links.lww.com/SIH/A192 Supplemental Digital Content 17). Double mix impressions of the cleft palate were made using Xantopren (Heraeus Kulzer GmbH, Hanau, Germany) to prepare class IV super hard stone casts (SHERAAQUA, SHERA Werkstoff-Technologie GmbH & Co. KG, Germany). In the next step, acrylic plates (Orthocryl, Dentaurum GmbH & Co KG, Ispringen, Germany) of 2 types were fabricated by an off-site orthodontic laboratory. Type 1 was fabricated as a conventional drinking plate, type 2 as a nasoalveolar molding plate (Fig. 2A, B). Compared with drinking plate, in nasoalveolar molding plate, a metallic nasal stent with a kidney-shaped acrylic ending extended from the molding plate. Positioning of the nasal stent below the alar rim and extraoral taping were performed according to the Grayson technique of nasoalveolar molding6 (Fig. 3).
Multiple-Choice Test Scores
The voluntary multiple-choice questionnaire was completed and handed back by 138 students. The CLP section of the test contained 4 questions on the treatment steps of CLP and the nasoalveolar molding technique (Table 1). The maximum achievable score for this test section was 4 points. In the preteaching test, 4 points were achieved by 6 students (4.3%), 3 points by 23 students (16.7%), 2 points by 53 students (38.4%), 1 point by 46 students (33.3%), and 0 point by 10 students (7.2%). In the postteaching test, 4 points were achieved by 29 students (21.0%), 3 points by 63 students (45.7%), 2 points by 31 students (22.5%), 1 point by 14 students (10.1%), and 0 point by 1 student (0.7%). When analyzing the total preteaching and postteaching scores of the CLP test section, an improvement of the test result was observed in 96 cases (69.6%). Twenty-three students (16.7%) performed similarly in both tests. A decrease of the test score occurred in 19 cases (13.8%). The t test for paired samples revealed a significant increase of the test score for questions 1 (P = 0.001), 3 (P < 0.001), and 4 (P < 0.001). For question number 2, there was only a slight increase noticed, which proved to be nonsignificant (P = 0.633). Table 2 and Figure 4 sum up statistical results.
Although prevalence rates of CLP differ quite substantially between different geographic regions1 and races,7 CLP has to be regarded as a prominent global health issue. In industrial countries and resource-limited areas alike, information deficits and lack of knowledge relating to CLP remain a problem and give rise to difficulties.8 According to a survey of 200 pregnant women in Nigeria, little more than half of them had heard of CLP, and only 19.8% of them associated this deformity with a defect on the lips. Only 7% of the women were informed about CLP by medical professionals.9 In a survey in industrialized countries among professionals of other specializations, some respondents have not yet even heard about the field of “oral and maxillofacial surgery” that is actually concentrated on doing the CLP treatment.2,10 Moreover, preprofessionals were not able to give a specific know-how compared with affected parents.11 For this reason, our aim was to make our students more aware of this issue by introducing a new haptic CLP model into our practical skill courses. There is a need for new approaches in the practical training of medical students and medical assistants,12 especially in surgical disciplines where excellent anatomic knowledge and manual dexterity is required. A haptic model was chosen because various haptic models have already proven to be effective in the past.13,14 The teaching tool should also be realistic, cost-effective, easy to compile, and resistant against wear. Moreover, it should be capable of being integrated into all sorts of teaching concepts and accessible for different target groups.
Of course, the model does not provide the opportunity to get in touch with real intraoral conditions. The material of CLP model is more or less rigid and does not simulate physiologic oral movements. This is the reason why we consider developing a follow-up version of the CLP model with closer-to-reality attributes of the material. Additional considerations also include the construction of a second CLP model with a bilateral cleft type. Undoubtedly, the model cannot provide an equivalent replacement for examinations of human newborns with CLP, but in reality, there are very few opportunities for students to see and examine newborns with CLP in their first days of life. On the model, exercises can be repeated as often as desired. Students do not have to fear mistakes that could possibly harm the patient. This is a valuable experience not only for those who intend to specialize in oral and maxillofacial surgery but also for those with interests in the fields of pediatrics, gynecology, or ENT because most of them will get in contact with patients with CLP in their professional career.
Cost-effectiveness is essential in constructing a model. On one hand, developing countries must be able to produce teaching models with minimal financial expenditure to make them available to as many people as possible. On the other hand, students tend to be slightly careless in their handling with models, which leads to a high wear. To guarantee a reasonable cost-benefit calculation, low production costs and a high resistance to wear are crucial factors. Fabrication of the CLP model was performed in a standard dental laboratory by 1 person in 35 hours of work. No special technical skills were necessary for production. Total expenditure for the used materials in the production process of our CLP model amounted to less than €200, excluding laboratory costs for the casts and plates. The model proved to be highly robust and showed no signs of wear at the end of the semester. It is easy to transport and does not require a special setup before use. The results of the test analysis showed that the students’ CLP-related knowledge significantly improved during the course. Nevertheless, it should be noted that in this study, we can only show the effectiveness of the CLP model by improved test scores. Additional practical testing would be of interest. Although we only tested this tool for students, we think that the CLP model can be equally used for different target groups such as hospital nurses, physicians, and clinical employees in other disciplines that are also involved in CLP treatment.
In our opinion, the CLP model is a useful teaching tool and has the capability to improve the level of expertise in the field of CLP.
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