... the treatment plan. The diagnostic setup is a fundamental aid and should be ... ascertain before orthodontic treatment how much space is available for tooth ...
F E A T U R E
This article has been peer reviewed
The Importance of the Diagnostic Setup in the Orthodontic Treatment Plan By Claudia Trindade Mattos, MD, PhD; Ana Carolina Rodrigues Gomes, DDS; Alexandre Antônio Ribeiro, MD; Lincoln Issamu Nojima, PhD; Matilde da Cunha Gonçalves Nojima, PhD
Abstract: The aim of this study was to address the importance of the diagnostic setup by examining two cases where diagnostic setups were made in order to determine the treatment plan. The diagnostic setup is a fundamental aid and should be used when there are doubts in the orthodontic planning.
ntroduction The importance of the diagnostic setup was first emphasized by Kesling.1-2 He introduced the setup made by dissecting the teeth from the original orthodontic models and replacing them, in wax, back on their bases, eliminating teeth which are supposed to be extracted when there is such a need. According to Moyers,3 many times it is most useful to ascertain before orthodontic treatment how much space is available for tooth positioning and the diagnostic setup is a very practical technique for doing so. Among the many uses and benefits acquired from the diagnostic setup are the recognition of possibilities and limitations of treatment, an understanding of the anchorage needs and of the mechanics indicated for each specific case, the opportunity to study all three dimensions of the denture with teeth positioned in the very best occlusion and consideration of tooth discrepancies in treatment planning.1-5 Since short- and long-term success of the orthodontic treatment can be established when all the therapeutic goals regarding the static and functional occlusion are achieved in the completion of treatment,6-7 the diagnostic setup is an important tool for anticipating the results of treatment and the necessary means to reach them. Despite the value of the diagnostic setup, especially in difficult or borderline cases, it continues to be overlooked by many professionals.
This paper addresses the importance of the diagnostic setup by examining two cases. In the first case, three diagnostic setups were made in order to determine the treatment plan that best fitted the case and that would bring the best results and stability for this specific individual. In the second case, one diagnostic setup was made to verify whether the intended treatment plan would be able to be carried out resulting in harmonic intraarch and interarch relationships. Material and Methods First case. A healthy 11-year-old boy (Figure 1) was brought by his parents for orthodontic treatment in Rio de Janeiro, Brazil. At the initial orthodontic evaluation he was already in the permanent dentition, with an Angle Class I malocclusion and a small mandibular arch-length discrepancy (-1.6 mm). The lateral cephalometric analysis (Figures 2 and 3) showed a Class I skeletal malocclusion (ANB, 4o), a harmonious facial growth (SnGoGn, 35o;
Figure 1. Pretreatment extraoral photographs of the first case. IJO VOL. 23 NO. 2 SUMMER 2012
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Figure 2. Pretreatment cephalometric radiograph of the first case.
Figure 3. Pretreatment cephalometric tracing of the first case.
Figure 4. Superimposition of the original tracing (black) and of the tracings of the treatment options for the first case: no extraction (blue), four premolars extraction (green) and one lower incisor extraction (red). 36
Figure 5. Pretreatment dental models of the first case.
y-axis-FH, 53o) and protruded maxillary and mandibular incisors (1.NA, 27o; 1-NA, 7 mm; 1.NB, 27o; 1-NB, 6 mm; IMPA, 91o). The lower left central incisor showed some gingival recession. The facial profile was convex (S-LS, + 2 mm; S-LI, + 6 mm). There was a tooth discrepancy with a mandibular excess of 1.7 mm. Total discrepancy of the lower arch was calculated by adding up the arch-length discrepancy and the cephalometric discrepancy (-5,6 mm). The treatment objectives for this patient were to enhance the profile, align the teeth and maintain the Class I relationship. The really small mandibular discrepancy made it difficult to decide for extraction of either a mandibular incisor or of four first premolars. In order to visualize the treatment results and to establish a treatment plan with confidence, three diagnostic setups were made with three alternative treatments: 1) no extraction and mild protrusion of incisors; 2) extraction of four premolars with retraction of the anterior teeth and mesialization of the posterior teeth; 3) extraction of a mandibular incisor (the one with gingival recession). Additionally, a treatment simulation was made through the Dolphin Imaging software (version 11.0, Chatsworth, CA, USA) for each treatment alternative, rendering a cephalogram for each simulation. A superimposition was made combining the original and the treatment simulations cephalograms (Figure 4). In order to construct the setups, the original models (Figure 5) were duplicated three times. Before each setup was made, the lower incisor position and the lower arch form were registered with brass wire. The position of the original malocclusion mid-line and the position and inclination of first molars of both arches were registered on the base of the models (with blue wax). Since the sagittal mid-line was coincident with the dental mid-line, it was not registered in the base of the models. The teeth were then identified and sewed from the models like Kesling proposed.2 The teeth were then waxed in the best possible occlusion, considering the treatment plan, the maintenance of the original arch form, correct contact points and axial inclination, maintenance of original intercanine and intermolar width, corrected and coincident mid-lines, Class I relationship, ideal overjet and overbite. The final waxing was completed and the gingival areas reproduced (Figures 6-8). IJO VOL. 23 NO. 2 SUMMER 2012
Figure 10. Pretreatment cephalometric radiograph of the second case.
Figure 6. Setup 1 models of the first case: simulation of treatment with no extraction.
Figure 7. Setup 2 models of the first case: simulation of treatment with extraction of four first premolars.
Figure 8. Setup 3 models of the first case: simulation of treatment with extraction of the lower left central incisor.
Figure 9. Pretreatment extraoral photographs of the second case. IJO VOL. 23 NO. 2 SUMMER 2012
Second case. A healthy 21-year-old woman (Figure 9) came looking for orthodontic treatment in Rio de Janeiro, Brazil. At the initial orthodontic evaluation she presented an Angle Class I malocclusion and a mandibular arch-length discrepancy of -2.4 mm. The lateral cephalometric analysis (Figure 10 and 11) showed a Class I skeletal malocclusion (ANB, 1o), a harmonious facial growth (SnGoGn, 30o; y-axis-FH, 54o) and protruded maxillary and mandibular incisors (1.NA, 35o; 1-NA, 10 mm; 1.NB, 25o; 1-NB, 7 mm; IMPA, 93o). There was a transposition between the lower right lateral incisor and the lower right canine. The facial profile was slightly convex (S-LI, + 2 mm). There was no tooth discrepancy. Total discrepancy of the lower arch was calculated by adding up the arch-length discrepancy and the cephalometric discrepancy (-8.4 mm). The treatment objectives for this patient were to align the teeth without damaging the profile and maintain the Class I relationship. Taking into account the total lower arch length discrepancy and the already protruded incisors, some extraction would be necessary. Two treatment alternatives were considered: 1) extraction of four premolars with retraction of the anterior teeth and mesialization of the posterior teeth; 2) extraction of a mandibular incisor (the transposed one). A treatment simulation was made through the Dolphin Imaging software for each treatment alternative, rendering a cephalogram for each simulation. A superimposition was made combining the original and the treatment simulations cephalograms (Figure 12). After analysis of this superimposition showing treatment effects on the profile, a setup was made after duplication of the original models (Figure 13) to make sure that the treatment option that included extraction of the transposed incisor could be finished with good intraarch and interarch relationships. The setup was performed (Figure 14) in the same way as the ones previously described. As there was no tooth discrepancy, some stripping had to be made on the superior incisors. 37
Results and Discussion On setup 1 of the first case (Figure 6), no teeth were extracted. The lower incisors were then slightly protruded so that they could be aligned. It is important to consider that this protrusion could worsen both the facial profile, as seen in Figure 4, and the gingival recession on the left central incisor, leading to an unfavorable result. On setup 2 of the first case (Figure 7), the four first premolars were extracted. The lower incisors were retracted 3 mm to their ideal position Figure 12. Superimposition of the Figure 11. Pretreatment and the lower first molars migrated original tracing (black) and of the cephalometric tracing of the mesially 3.5 mm each. In this alternative tracings of the treatment options for second case. the second case: one lower incisor of treatment, the facial profile would be extraction (red) and four premolars altered (Figure 4), improving esthetics extraction (green). and making the face of the patient more harmonious. Additionally, since the left lower central incisor would be retracted, the gingival recession would tend to diminish. On setup 3 of the first case (Figure 8), the lower left central incisor was extracted. The lower incisors were minimally retracted (1 mm). The upper incisors were submitted to a stripping process to eliminate tooth discrepancies created by the extraction. The facial profile would be just slightly altered (Figure 4) by the minimal retraction provided in this treatment alternative, but the gingival recession would no longer be a problem, since the affected tooth would be extracted. In this specific case, there are three alternatives. In all of them, it is likely that a good occlusion be achieved, as foreseen in the Figure 13. Pretreatment dental models of the second case. setups. However, only the option comprising the extraction of four premolars would allow a retraction of the incisors and their correct positioning on the basal bone. According to Tweed,9 mandibular incisors must be upright over the basal bone if balance and harmony of facial proportions are to be achieved in orthodontic treatment. This concept is confirmed in Strang’s10 description of normal occlusion. Consequently, this was also the only option of treatment that would affect the facial profile favorably. If this is an important aspect for the patient and his parents, this should be the alternative chosen. Nonetheless, if the patient and his parents strictly refuse a treatment with extractions, the first alternative should be chosen, but they must be responsible for Figure 14. Setup models of the second case: simulation of this choice and must be aware of the consequences treatment with extraction of one lower incisor. it may bring. 38
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The treatment cephalometric simulation of the second case showed that the extraction of four premolars and retraction of the anterior teeth would provide a concave profile with retruded lips, which might accentuate the already prominent nose of the patient. Therefore, the option of extraction of one lower incisor (the transposed one) seemed more reasonable with the advantage of favoring the mechanics by eliminating the need of correction of the transposed incisor. However, this alternative would require a considerable amount of stripping in the upper incisors and canines. A setup (Figure 14) was helpful to determine the amount of stripping necessary for each tooth and the final best possible occlusion. The setup is an important tool, which can help the discussion of the treatment plan with the patient and his parents. They can visualize the alternatives in question and understand the best alternative of treatment. According to Sandler et al.,8 effective communication is a difficult process by itself and, hence, the use of visual aids is becoming increasingly important to illustrate the proposed treatment and possible outcome. In conclusion, the diagnostic setup is still a fundamental aid in orthodontic planning, as it provides beforehand the three-dimensional representation of the occlusion by the end of treatment, and should be used in every case where tooth discrepancies, agenesis, tooth extractions, asymmetries, or other treatment planning raises doubts about the final result. The orthodontist may evaluate the different alternatives of treatment by constructing as many setups as needed,11 which will help him in making decisions, in recognizing the possibilities and limits of the treatment and in determining the anchorage and mechanics to be used. Although digital4 and photographic8 setups have been proposed lately as an interesting alternative or additional method, the conventional wax setup is still a visual tool and the only palpable aid for both patients (or their parents) and the professional. References 1. 2. 3. 4. 5. 6.
Kesling HD. Predetermined pattern as diagnostic aid. Am J Orthod Dentofac Orthop 1947;33(1):43-44. Kesling, HD. The diagnostic setup with consideration of the third dimension. Am J Orthod Dentofac Orthop 1956;42(10):740-748. Moyers RE. Handbook of Orthodontics. 4th ed. New York: Year Book Medical Pub, 1988. Macchi A, Carrafiello G, Cacciafesta V, Norcini A. Threedimensional digital modeling and setup. Am J Orthod Dentofac Orthop 2006;129(5):605-610. Wilson MD, Sinha PK, Prasad HS. A quick and easy diagnostic setup technique. J Clin Orthod 1998;32(5):328-329. Oltramari PVP, Conti ACCF, Navarro RL, Almeida MR, AlmeidaPedrin RR, Ferreira FPC. Importance of occlusion aspects in the completion of orthodontic treatment. Braz Dent J 2007;18(1):7882.
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Hoffman BD. Indirect bonding with a diagnostic setup. J Clin Orthod 1988;22(8):509-511. 8. Sandler J, Sira S, Murray A. Photographic ‘Kesling set-up’. J Orthod 2005;32: 85-88. 9. Tweed CH. Clinical Orthodontics. 1st ed. Saint Louis: The C. V. Mosby Company, 1966. 10. Strang RHW. A text-book of Orthodontia. 3rd ed. Philadelphia: Lea & Febiger, 1950. 11. Knierim RW. A simplified wax setup technique. J Clin Orthod 1975;9:305-307.
Claudia Trindade Mattos, MD, PhD, is a student in the Department of Orthodontics at Federal University of Rio de Janeiro.
Ana Carolina Rodrigues Gomes, DDS, is a dentist graduated by the Federal University of Rio de Janeiro.
Alexandre Antônio Ribeiro, MD, is in the Department of Orthodontics, Federal University of Rio de Janeiro.
Lincoln Issamu Nojima, PhD, is a Professor in the Department of Orthodontics at Federal University of Rio de Janeiro.
Matilde da Cunha Gonçalves Nojima, PhD, is a Professor in the Department of Orthodontics at Federal University of Rio de Janeiro.
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