Change in the Vertical Relation in Class II Deformity with Skeletal Open Bite in the Orthognathic Surgery

The continuously growing esthetic awareness for the facial appearance and the spreading of information about the possibilities of adult treatment by public media result in an increase of adult patients seek orthodontic treatment to improve their facial esthetics. In general, these patients show such a severe skeletal deformity that it is detectable even by non-experts because of its extraoral manifestation, which is the main motivation for treatment. Because of the nature of these deformities and because of the lacking growth usable for therapy the only promising treatment for these patients is the combined orthodontic-surgical approach. Besides a stable and functional occlusion with physiologic position of the condyle, the goals of treatment are the improvement of the dental and, above all, facial esthetics since the patient judges the success of treatment mostly by the extraoral appearance. The dentofacial appearance must be defined prior to treatment to plan the individual right approach in knowledge of the different treatment possibilities for Angle Class II deformities and thus be able to reach both sides –patient and orthodontistsatisfying result. With this article a systematic therapy concept to treat patients with Class II deformities and skeletal open bite with a long lower face (long face syndrome).


Introduction
Pre-surgical orthodontic preparation was uncommon for patients requiring orthognathic surgery until the 1960's. However, as surgical techniques advanced and the number of patients choosing an orthognathic approach increased, the patients' and clinicians' desire for optimal esthetic and occlusal results led to the most common current treatment approach. This approach involves pre-surgical orthodontic decompensation of the occlusal relationships and attainment of normal dental alignment. As most orthognathic treatment is planned now, there are two phases of orthodontic tooth movement, namely before and after orthognathic surgery. The disadvantages of having orthodontic interventions both before and after orthognathic surgery include a long treatment time and temporary worsening of facial appearance. Many patients become discouraged. [ 1,2,3] Ever since the first orthognathic surgery procedure was performed by Hullihen in 1848, many new techniques and methods have been introduced. The introduction of orthognathic surgery widened the possibilities for treatment of severe malocclusions which could not be treated by orthodontics alone. As shown by Kondo and her colleagues, the limits of orthodontic treatment alone for severe malocclusions are broadening, but the underlying skeletal imbalances remain. Until the 1960's, orthognathic surgeries were usually performed without any pre-surgical orthodontic treatment. In fact, when Hullihen performed the first mandibular sub-apical osteotomy on a burn victim, he was able to correct the prognathism but created an edge-to-edge occlusion anteriorly [ 29 ] The three stage philosophy of orthognathic surgery was later adapted and is still valid today in the majority of cases. These stages involve pre-orthognathic orthodontic treatment to relieve the dental compensations followed by the orthognathic surgical procedure and finally post-surgical orthodontics to finish the case and settle the occlusion.

History and Initial Examination
The 21-year-old female patient reported first to the prosthodontic department for the replacement of lost lower anteriors because of an accident 6 months prior to the first consultation. Lower left canine and incisors were missing and there was an extensive loss of alveolar bone in this region. In addition to the total luxation there were crown fractures in the fourth quadrant. The patient also complained about pain of the temporomandibular joints when chewing which initiated before the accident and she felt an esthetic impairment because of rotated and crowded upper incisors.
The functional analysis showed that because of the impeded lip closure the mandible is habitually protruded to make mouthclosure possible. Thus the condyles were displaced out of their physiologic position ventral and caudal towards the articular eminence. . [ 31 ] There was a corresponding functional anterior shift of the mandible from centric relation to maximum intercuspidation (habitual occlusion).

Diagnosis
The diagnostic records were taken in habitual occlusion as well as in centric relation ( Fig. 1a, b, Fig. 2 a-e, Fig. 4). For diagnosis and treatment planning the records with centric relation were taken.
Not only for diagnostic (centric relation) but also for therapeutic (TMD-symptoms) reasons a flat plane splint was inserted for 5 weeks which led to an improvement of the symptoms. In addition, the whole extent of the anterolateral functional shift (forced bite) was evident, the mandible was much more dorsal and deviated to the right so that there was a nonocclusion on the left side.     The facial photographs show insufficient mouth-and lipclosure in the centric relation and the described deviation of the mandible to the right. The lateral facial picture shows a posterior divergent face with protruded lip prominence and compared to the mid-face a long lower face -57% : 43% instead of 50%:50% (Fig. 2) . [ 33,34 ]. The Patient had a class II deformity with a mandibular midline shift to the right, a circular open bite and nonocclusion on the left side( Fig.  2a-d). In the upper jaw an arch length discrepancy of 5mm existed. The lower jaw showed the reduced number of teeth and the fractures of the lower right second premolar and second molar as consequence of the accident.
The orthopantomogramm (Fig. 4)shows the bone loss in the lower front due to the avulsion of the teeth and the wire Open Journal of Dentistry and Oral Medicine 3(1): 13-20, 2015 15 for the temporary prosthodontic replacement of the lost teeth. Lower right second premolar showed a deep complicated fracture; clinically a grade III mobility was apparent because of the loss of the lingual bone and thus had to be extracted. In addition to the crownfracture of the lower right first molar had an apical lesion. All third molars were erupted and in the lower arch partially covered with gingiva. The most hurting right condyle showed an uneven dent ventral, the left condyle a deformation. The greater abnormality of the right condyle might be caused by the medioventral forced bite.
Cephalometric analysis in centric relation elucidates a vertical and sagittal skeletal as well as soft tissue deformity. The values indicated a skeletal open bite with mild extraoral manifestations of a long face syndrome: Distobasal jaw relation, increased interbase angle (ML-NL= 33°) because of the posterior rotation of the mandible (ML-NSL= 39°) and anterior rotation of the upper jaw (NL-NSL = 6°), slightly reduced ratio of upper to lower facial height (PFH/PFH = 60%) while growth had been balanced. Because of the loss of lower teeth the dental analysis was reduced to the upper jaw. The vertical distribution of the soft tissue profile showed a disharmony of upper to lower face (G´-SN : Sn-Me´ = 43%:57%). This could also be seen in the bony structures (N-Sna : Sna-Me = 40%:60%). There was also a disharmony in the lower face (Sn-Stms-Me´ = 30%:70%) . [ 8,9,34,48,49,50 ].
These changes in the ratio were not because of an alteration of the upper lip but more because of a lengthened lower face (, Table 1). Besides the stated treatment goals it was the special aim to improve facial esthetics not only in the sagittal but also in the vertical dimension. This was to be obtained by relatively shortening the lower face. Shortening of the lower face as causal therapy with corresponding effects on facial esthetics and lip function could be established only with a combined orthodontic-surgical approach [ 37,48 ]. By solely orthodontic measures the pursued aims concerning esthetics and function could not have been reached. The deformity was too severe for a dentoalveolar compensation. Thus a bimaxillary osteotomy was planned for surgery. To improve the vertical dimension an impaction of the maxilla was necessary which should be greater dorsal than ventral. As consequence of the impaction the mandible with the condyles as "centers of rotation" . [ 43 ] was supposed to autorotate sagittal and vertical; thus a displacement ventral and at the same time cranial of the pogonion was to be expected (Fig. 5 a, b) . [ 21,22,23,26,45,51 ].For total correction of the sagittal deformity a surgical advancement of the mandible was planned because the autorotation of the mandible was regarded as nonsufficient for the correction of the distal occlusion.

Treatment
The case was treated according to the Würzburg treatment concept for orthognathic correction of a skeletal deformity and consisted of 4 phases . [ 48,49,50 ]: I) Presurgery Measures and Orthodontic Setup 1) "Splint therapy": A flat plane splint was inserted for 5 weeks to establish a physiologic centric relation of the condyles for final treatment planning and to reduce the 16 Change in the Vertical Relation in Class II Deformity with Skeletal Open Bite in the Orthognathic Surgery temporomandibular joint pain. Thus the forced bite could be diagnosed to its whole extent. [ 10,11 ]. Diagnostic records with the wrong position of the condyles (because of the forced bite) would have led to a wrong diagnosis, treatment planning and not at last to a treatment with corresponding consequences for the result . [ 52,53 ] 2) Orthodontic Preparation: The aim of orthodontic preparation was to develop the dental arches, to harmonize them in the three dimensions of space and to eliminate the dental compensation of the skeletal deformity. Decisive for the preparation was the protrusion and torquing of the upper anterioirs not only to eliminate crowding but also with regard to the following surgery whereby the maxilla is impacted and rotated posteriorly. This procedure results in a more retruded position of the anteriors which must be taken into account in the preparation. Thus the presurgical labial inclination could be tolerated. For orthodontic preparation a multibracket appliance (0.022 bracket slot) was used. In the upper arch the first arch wire was a 0.014 NiTi. The missing teeth in the lower jaw were replaced with artificial teeth which were ligated to a 0.016x0.022 inch thermoelastic archwire. Further arch wires were a 0.018 inch NiTi in the upper arch and 0.018x0.025in NiTi followed by a 0.019x0.025in steel in both jaws. The presurgery orthodontic phase lasted 7 months.
3) "Splint therapy" to establish the centric relation 3-4 weeks prior to surgery. Aim of this procedure is to register a physiologic position of the condyle (centric relation) . [52,53 ]. An inaccurate position of the mandible results in an incorrect planning of the amount of advancement and with that in an inevitable relapse.  After surgery on the casts, determining the amount of advancement and fabrication of the splints according to the system used in Würzburg (Four-splint-system: beginning splint or registering splint, maxilla impaction splint, mandible autorotation splint, finishing splint) [ 37,38,47 ]. a LeFort-1 osteotomy of the maxilla was performed where the maxilla was impacted cranial: 4mm dorsal and 2mm ventral so that a posterior rotation of the whole maxilla resulted. With the autorotation of the mandible part of the sagittal deformity could be corrected. The rest of the correction was achieved by a bilateral sagittal split osteotomy of the ramus according to Obwegeser-Dal Pont. [ 15,16,39,40,41 ]. The surgical advancement was 6mm on the right and 2 mm on the left side with a side shift of 4.5mm to the left (Fig. 6 a, b). Fixation of the proximal condyle bearing segment in centric position during surgery is a standardised procedure in our Treatment Strategy to keep three dimensional control of the condyles [ 35,36,46,47 ] (Fig. 7)

III) Postsurgery Orthodontics for Finishing
The earliest possible application of orthodontic forces after surgery is crucial to their impact. muscular forces are eliminated which otherwise would counteract tooth movements.
Thus on the 4 th day after surgery postsurgery orthodontics were initiated [ 48,49 ] with insertion of up and down elastics and for orientation of the muscles to the new position of the mandible light Class II elastics. This phase lastet 3 months.

IV) Retention
Unwanted side effect from a mandibular advancement is the readjustment and reorientation of the affected soft-tissue and muscles and with that their force against the new position of the mandible. An advancement with transitional movement of the mandible results in stretching and strain of soft tissue and the suprahyoid complex. This tension must be regarded as relapse promoting [ 12,19,20,24,48,49 ] , . Because the amount of advancement was high and the patient had tense and short muscles of the suprahyoid complex a physiotherapeutic treatment was prescribed to support the rehabilitation and reorientation of the muscles to their new position. To support the muscles in their adaptation to the new situation a bimaxillary appliance is suggested for retention-e.g. a bionator. A bionator was fabricated and inserted on the day of debanding. In addition a suck-down splint with artificial teeth to replace the lost incisors was inserted.
2,5 months after completion of orthodontic treatment prosthodontics were initiated. The patient received fixed restorations from lower left scond premolar to the right canine, two blocked crowns for the lower right first and second molar and an appendix to that block for replacement of the right second premolar.

V) Result and Discussion
The introral pictures show the final situation after prosthodontic rehabilitation (Fig. 8a-d). Class-I occlusion on both sides and harmonising arches could be achieved. The extraoral pictures show a harmonic division of the face in the vertical dimension which was accomplished by shortening the lower face with surgery and a harmonic profile in the sagittal dimension. Profile of the mouth and lipclosure is physiologic (Fig. 9a, b).  The cephalograms show the change of the variables (Fig.  10a, b, table 1). Because of the surgical impaction and the posterior rotation of the maxilla the inclination of the maxilla was increased by 2°. With that and the following autorotation of the mandible the interplane angle was reduced by 5°. Impaction and autorotation resulted in a decreased anterior face height, which increased the posterior to anterior face height (PFH:AFH=64%) and thus harmonised this ratio. The vertical division of the skeletal and soft tissue profile shows a harmonisation. The ratio of skeletal upper to lower face is 45%:55%. The disharmony of the lower third of the face was corrected so that the ratio Sn-Stm : Stm-Me´ equals 1:2 (33%:67%). Superimposition of the cephalograms in S-N-S show the skeletal and soft tissue changes in the sagittal and vertical dimension (Fig. 11). Is the position of the pogonion in the sagittal plane checked one can see that the distance between post treatment and pre treatment is larger than the surgical advancement of the mandible. This is due to the autorotation of the mandible after impaction of the maxilla which is partially responsible for the correction of the distal occlusion [ 21,22,23,26,32 ]. The changes in the posterior teeth in the vertical and partially in the in the sagittal dimension are also effects of the impaction of the maxilla and autorotation of the mandible. The panoramic radiograph (Fig 12) after insertion of prosthodintics show the material of the osteogenesis and the replacement of teeth in the anterior and posterior segment. In accordance with the results of Radney&Jacobs [ 42 ] concerning cranial displacement of the pronasal point, follow up studies of Collins and Epker 14 and Rosen 43 concerning raising of the tip of the nose with impaction of the maxilla these effects could also be seen in the presented case. These results were also confirmed independently by several authors [ 4-7, 13, 17, 25, 27, 28, 30, 33-42 ], and especially by De Assis et al. [ 18 ] and Lee et al. [ 33 ].
The patient is clinically symptomless, joint-and chewing function as well as mobility of the mandible are unlimited.
The Patient was satisfied with the accomplished functional and esthetic situation after treatment.

Conclusions
By means of the systematic treatment approach presented, class II deformities with a skeletal open bite and long lower face can be treated with predictable success and without esthetic compromises. The treatment result shows that it is necessary to adapt the dentoalveolar Sitation to the skeletal dysgnathia to end with a satisfactory result with respect to function, esthetics and stability. It can be concluded that it is only possible to reach the preset treatment goals with an exact diagnosis and knowledge of the necessary orthodontic preparation in combination with the surgical procedure.