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Dental Tribune Middle East & Africa Edition

28 Dental Tribune Middle East & Africa Edition | May - June 2014ortho tribune > Page 29 Aesthetics and function: Orthodontic – surgical collaboration as a key to success ByDrsMartinJaroch& FriedrichBunz,Germany O ral surgery is an im- portant cornerstone in orthodontic treatment of malocclusions. Tooth move- ment is only possible to a limited extent and always depends on the misalignment of the maxilla and mandible in relation to each other, as well as on deformities of the jaw in relation to the other facial bones. Abnormalities may be congeni- tal or acquired and may affect patients in childhood already. If so, the focus of orthodontic treatment is not primarily in the aesthetic correction, but is guided by functional and pro- phylactic concerns. Efficient oc- clusion and restoration of mas- ticatory function are decisive factors for tooth preservation and prevention of secondary disorders (Figs. 1a–c). Without a doubt, aesthetic improve- ment, as well as the associated self-consciousness, is the main concern of most patients, which can be pursued through surgi- cal correction. Causes of malocclusion Generally, patients visit an orthodontic practice only after symptoms or significant abnor- malities have already present- ed. Clinically, this results in late mixed dentition or permanent dentition, which can compli- cate an accurate mapping of the reasons for this malocclusion. In the literature, the causes of malocclusion and the aetiologi- cal structure of the symptoms of malocclusion in orthodontic pa- tients are controversial issues. No explicit information on the percentage of patients with ac- quired or congenital malocclu- sions can be found in a study by Schopf (1981) on the exogenous factors that are involved in the development of malocclusion. However, from the assessment of individual patients’ symp- toms, all symptoms of maloc- clusion could be associated with exogenous aetiological factors only in 48% of patients. Brodmann and Saekel (2001) concluded from Schopf’s report that only 20% of the anomalies were hereditary and thus could not be affected by prophylactic interventions. Accordingly, 80% of malocclusions could be re- solved through prevention and better oral hygiene. This idea is contrary to the results of the German Oral Health Study. In this study, a decrease in child- hood caries was observed. How- ever, clinically these results werenotassociatedwithalower rate of and need for orthodontic treatment. The study at the Uni- versity of Greifswald, Germany, found that 20.3% of the symp- toms were genetically deter- mined, 44.3% were exogenous and 35.3% were not precisely defined. Based on these results, the assumption that 80% of malocclusions can be resolved by prevention and better oral hygiene is very questionable (Hensel, DGKFO opinion, 2001). The varying findings and re- marks illustrate the difficulty of clear classification of malocclu- sion. Nonetheless, the demands of the patient have priority and he expects a symptom-based therapy with stable treatment results. This means that in mal- occlusion cases that cannot be resolved by functional ortho- dontics solely, orthodontic–sur- gical planning can be done be- fore any treatment is attempted by pure dentoalveolar compen- satory intervention. Compensa- tory dentoalveolar procedures could prevent a surgical opera- tion. At the same time, patients may run the risk of protracted treatment without any long- lasting benefit. The decision for or against orthopaedic sur- gery requires interdisciplinary agreement and reliable treat- ment goals must be defined in advance (Figs. 2a & b). Target group for orthopaedic surgery Nowadays, adults make up the majority of patients in the orthodontic practice. They are generally motivated by high socio-cultural demands and the desire for perfect teeth. In adults who have an obvious dis- crepancy between their maxilla and mandible, it must be clari- fied whether the deformities are dentoalveolar or skeletal. Owing to the limitations of con- ventional orthodontic treat- ment, skeletal discrepancies can rarely be entirely resolved. In those cases, combined orth- odontic–surgical treatment is necessary. During growth, it is mostly possible to treat maloc- clusions successfully without surgery by purely orthodontic treatment using removable ap- pliances or brackets. Children and young people for whom functional orthodontic treatment has not led to the de- sired result are treated surgical- ly after the growth period. Early surgery always carries the risk of unexpected growth pattern or unilateral abnormal hyper- plasia and can affect the results of the operation. Selection of patients Combined orthodontic–sur- gical treatment requires not only strong and focused inter- disciplinary collaboration, but also absolute acceptance of the treatment plan by patients and parents. The treatment is time- consuming and post-operative corrections cannot be excluded. A detailed medical preopera- tive discussion should inform patients about the risks of com- bined treatment and the conse- quences of untreated malocclu- sions. Malocclusions can cause numerous side-effects, such as back pain and chronic head- aches(Figs.3a&b).Inmarkedly dolichofacial face types, maloc- clusions can lead to a pharyn- geal constriction, which can manifest as obstructive sleep apnoea syndrome (Hochban et al. 1997). In adult patients, it is normally useful to determine the amount of malocclusion and force bite using a flat-plane bite splint. The splint is worn for six to eightweeks,andguaranteesthe identification of the physiologi- cal condylar position. Pursuing orthodontic correction depends on the intended post-operative situation. Therefore, such cor- rection is only dentoalveolar and does not transfer bite forces Fig. 1a-c: Deep bite, prognathism and latero-gnathia: according to clinical evaluation, they can be resolved only through interdisci- plinary treatment. Fig. 2a-b: Significant changes between the initial assess- ment of latero-gnathia in 2007 (a) and the beginning of combined orthodontic?surgical treatment in 2011 (b; 19-year-old patient). Fig. 3a: Side view of a 19-year-old patient: latero- gnathia is visible in the lower lip area. Fig. 3b: Frontal view: latero-gnathia to the right and the resulting devia- tion is clearly visible. Fig. 4a-c: Orthodontic, prepared pre-op diagnostic radiology (or- thopantomograph, cephalometric radiograph and antero-posterior projection) of the now 20-year-old patient. Fig. 5a-e: Pre-op clinical situation after orthodontic preparatory work. (Figs. 4a–c & 5a–e). The most fa- vourable position of the maxilla and mandible is assessed on the basis of simulated cast surgery in which the amount of shift is determined. Using these casts, a splint can be fabricated and placed during surgery to fix the determined physiological con- dylar position preoperatively (Figs. 6a–c). Teenagers with mandibu- lar asymmetry that cannot be clearly classified should be treated with special care. Should clinical records be avail- able only from the age of 16— whether as a result of erroneous dental records or simply owing to late initial assessment in a specialised practice—accurate early diagnosis of potential uni- lateral hyperplasia with further growth tendency is essential. According to the German So- ciety of Oral and Maxillofacial Surgery guidelines, a nuclear medicine diagnostic is neces- sary—in addition to inspection, palpation and radiography—to determine the risk of an abnor- mal growth in time. Through increased uptake in the affected region during scintigraphy, it is possible to draw conclusions about the growth’s behaviour. If the jaw continues to change by abnormal bursts of growth, it is advisable to postpone surgi- cal therapy until the cessation of growth. Surgical technique The choice of technique for the osteotomy depends on various factors. In displacement oste- otomy, surgical access to the bone is created, which is split at fixed points. Correction of the bone and bone healing in the new fixed position is accom- plished using simulated cast surgery and a fabricated splint. Following surgical modification of the jaw area, it is important to consider the correct position of the jaw and optimal occlusion. This crucial step has to be per- formed by the orthodontist as accurately as possible because repositioning and the degree of displacement of the jaw depend on achievable occlusion. Fur- thermore, teeth have an influ- ence on access to the surgical field and wisdom teeth must be removed before osteotomy in certain cases. Osteotomy can be done on both jaws or can be limited to the maxilla or mandible. However, in many cases it is functional to perform bimaxillary osteotomy and to shift both jaws. Today, generally the entire tooth-bear- ing portions of the jaw are shift- ed. Segmental osteotomy has not been proven to be very suc- cessful in the past and correc- tions of malocclusions are left to the orthodontic treatment part- ners. In this field of treatment, the Obwegeser–Dal Pont surgi- cal technique is recommended. This procedure describes an intra-oral stepped osteotomy at the mandibular ramus (Figs. 7a & b). Since Bell and Epker described the possibility of bi- maxillary surgery as the “down fracture” technique in 1975, it has been popular and today you can find it mostly as a combi- Fig. 6a: View of the casts in the articulator after successful simulation of surgery.

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