Condylar position and mandibular function after bilateral sagittal split osteotomy.

AIM: The purpose of this retrospective study was to perform an evaluation of postoperative positional changes of the condyle and mandibular function after bilateral sagittal split osteotomy (BSSO) with manual proximal segment positioning. PATIENTS: 45 patients were divided into the 2 groups ‒ G1 (advancement ‒ 14 patients) and G2 (setback - 31 patients). Rigid internal fixation screws were utilized in all cases. Inclusion criteria were only BSSO, no TMJ symptoms preoperatively and age 18 or older. RESULTS: The differences between pre- and postoperative condyle position were evaluated using measurements taken from preoperative CT scans and compared to CT scans made a minimum of 6 months postoperatively. The positional changes in both the axial and sagittal planes were measured and compared. The recovery of mandibular function was evaluated by measuring maximal interincisal opening (MIO). The results revealed that condylar positional changes after BSSO in both groups were minimal and not significantly different for all three dimensions measured. The recovery of mandibular function was faster in the group G2 than in the group G1. Mandibular function reached almost preoperative level in 6-12 months postoperatively in both groups. CONCLUSION: The results demonstrated that following BSSO, only insignificant condylar displacement and functional changes occurred within 6 to 12 months postoperatively (Tab. 4, Fig. 2, Ref. 47).

Long-term results of maxillary distraction osteogenesis in nongrowing cleft: 5-years experience using internal device.

Patients with cleft lip and palate (CLP) related deformities frequently have maxillary hypoplasia in all dimensions. These patients usually present with class III malocclusions, retruded midfaces and narrow hard palates. The skeletal problems can be treated by means of Le Fort I maxillary procedures. Surgical and orthodontic correction of severe maxillary hypoplasia, as often seen in CLP patients, has however proved to be challenging. The magnitude of the advancement is often hampered and the post operative stability significantly affected by palatal soft tissue scarring. The slow distraction of bone and the histogenic abilities of distraction osteogenesis (DO) have made it an atractive alternative treatment option for the management of maxillary hypoplasia in these patients. This paper presents the treatment results of 15 nongrowing CLP patients with severe maxillary hypoplasia treated by means of intra oral distraction. The mean anterior distraction of the maxillas was 12.7 mm (9-15.0 mm). The long-term cephalometric and clinical evaluation after a minimum of 60 months (mean follow-up 71 months) proved to be stable. The treatment results revealed, that distraction osteogenesis in nongrowing CLP patients with severe maxillary hypoplasia proved to be a predictable and stable option (Tab. 2, Fig. 3, Ref. 26).

Skeletal stability following mandibular advancement with and without advancement genioplasty.

The correction of most cases of skeletal class II mandibular deficiency requires surgical advancement of the mandible for treatment of the malocclusion. Often genioplasty is included in the procedure to improve the soft tissue profile. Long-term skeletal stability is an important goal for the surgeon and orthodontist following bilateral sagittal split osteotomy (BSSO) and is influenced by the muscles attached to the mandible. Following the surgical advancement of the mandible, the suprahyoid muscle complex is stretched and even more so when the procedure is combined with surgical advancement of the chin. This retrospective comparative study determined the long-term skeletal stability of patients who had undergone surgical advancement of the mandible by means of BSSO with an advancement genioplasty, compared to those who had undergone mandibular advancement surgery (BSSO) without an advancement genioplasty. This study concluded that the postoperative hard tissue relapse following BSSO advancement, with or without genioplasty, was clinically insignificant.

Medial pterygoid muscle and stylomandibular ligament: the effects on postoperative stability.

The postoperative skeletal stability following surgical advancement of the mandible can be influenced by several factors. The effect of the medial pterygoid muscle and the stylomandibular ligament on the stability of results following surgical advancement has possibly been underestimated. In this retrospective study, the long-term postoperative skeletal stability following surgical advancement of the mandible in two groups of patients was studied and compared. In one group the medial pterygoid muscle and the stylomandibular ligament were stripped from the medial side of the angle of the mandible during the bilateral sagittal split osteotomy (BSSO) procedure while for the other group of patients these muscles and ligaments were left attached. The long term skeletal stability of the two groups was compared and the group that had the muscles and the ligaments stripped proved to be more stable than the other group.

Variations in the anatomical dimensions of the mandibular ramus and the presence of third molars: its effect on the sagittal split ramus osteotomy.

The authors undertook a prospective study to evaluate the influence that the anatomical dimensions of the ramus of the mandible and the presence of lower third molar teeth may have on the sagittal split ramus osteotomy. The anatomical dimensions measured included the width of the anterior mandibular ramus, the height of the corpus posterior to the second mandibular molar and the antero-posterior anatomical position of the lingual. The influence that these dimensions of the mandible may have on the successful splitting of the mandibular ramus was investigated. The effect that the presence of wisdom teeth had on the difficulty of the procedure was also investigated. This study found that, unlike the presence of third molars, there was no single anatomical measurement that contributed to the level of difficulty of the sagittal split osteotomy. For descriptive purposes the authors proposes a classification of the four typical patterns of unfavourable splits.

Postoperative skeletal stability following clockwise and counter-clockwise rotation of the maxillomandibular complex compared to conventional orthognathic treatment.

Rotation of the maxillomandibular complex (MMC) and the consequent alteration of the occlusal plane (OP) angulation is a well documented orthognathic surgical design. This study presents a comparison of the long-term postoperative skeletal stability following clockwise rotation (CR), and counter-clockwise rotation (CCR) of the MMC with the skeletal stability of patients treated according to conventional treatment planning principles. The long-term postoperative skeletal stability of the (CR) group and the (CCR) group of patients were found to compare favorably with the group of patients treated by conventional treatment (CT) planning. The long-term postoperative stability of all three groups also compared well with skeletal stability reported in the literature following double jaw surgery.

The Le Fort I downsliding osteotomy: a study of long-term hard tissue stability.

Surgical maxillary repositioning in individuals with vertical maxillary deficiency may be accompanied by skeletal instability. Long-term skeletal changes in 13 patients who underwent a Le Fort I downsliding osteotomy were studied retrospectively. Nine patients underwent a single-jaw procedure, and 4 patients underwent a bimaxillary procedure. Rigid fixation was used in 10 patients, and wire osteosynthesis was used in 3. Descriptive statistics, Pearson moment correlation, and significance testing were performed at the 5% level. The maxilla was stable horizontally over the long term, but it underwent a mean 26.7% superior relapse anteriorly. The results were variable, however. Rigid internal fixation appeared to enhance the horizontal stability of the maxilla in patients who underwent single-jaw surgery. The maxilla was more stable vertically in patients who underwent bimaxillary surgery with rigid internal fixation, compared to isolated maxillary surgery and rigid internal fixation. The results indicate that a 2-mm relapse value may be useful in planning the vertical amount of maxillary incisor exposure.

Lingual orthodontics and orthognathic surgery.

Lingual orthodontics is an appealing option for patients requiring orthognathic surgical correction, since these patients are invariably adults or mature teenagers who are no longer at the usual "orthodontic age." Appearance is undoubtedly the most important motivating factor for adults seeking orthodontic treatment, and since the more physically attractive person has the advantage over the not-so-attractive person, it is self-evident that these patients would prefer an appliance that is less visible. Using the Ormco, Creekmore, or Begg lingual appliances in the maxillary arch and a labial appliance in the mandibular arch, the authors have successfully treated a variety of dentofacial deformities with a combined lingual orthodontic and surgical approach. The aim of this article is to establish some guidelines for the treatment of a variety of surgical cases and to highlight what are perceived to be the advantages and disadvantages of these 3 lingual appliances in the treatment of orthognathic cases and of the lingual orthognathic approach in general.

Surgical cephalometric prediction tracing for the alteration of the occlusal plane by means of rotation of the maxillomandibular complex.

The surgical cephalometric prediction tracing involving the alteration of the occlusal plane differs from the conventional surgical prediction tracing. When conventional surgical prediction is developed, the final occlusal plane is dictated by the occlusal plane of the mandible, with or without autorotation. The mandible (and therefore the mandibular occlusal plane) will rotate around a point at or just posterior to the condyle. This principle is not adhered to in treatment planning requiring rotation of the maxillomandibular complex and consequent alteration of the occlusal plane. The aim of this paper is to present a method for developing a surgical cephalometric prediction tracing involving rotation of the maxillomandibular complex.

Surgical manipulation of the occlusal plane: new concepts in geometry.

Rotation of the maxillomandibular complex and the consequent alteration of the occlusal plane angulation to improve functional and esthetic results have been well documented. The decision to change the occlusal plane angulation cannot be arbitrary and is made only when desired results cannot be obtained by conventional treatment planning. The geometry of rotation should be accurately planned by establishing a specific point around which the maxillomandibular complex should be rotated to achieve specific esthetic results. Treatment planning using anterior nasal spine and maxillary incisor tip as rotation points has been described and results demonstrated. This article will introduce additional points of rotation that may be considered based on a triangle constructed during treatment planning. Two clinical examples are presented in which these types of rotation were implemented.

Screw osteosynthesis compared with wire osteosynthesis in advancement genioplasty: a retrospective study of skeletal stability.

OBJECTIVE: To compare the skeletal stability of wire and screw fixation after advancement genioplasty. DESIGN: Retrospective study. SETTING: Teaching hospital and private practice, South Africa. SUBJECTS: 40 Patients who required advancement genioplasty, 20 in each group. INTERVENTIONS: Advancement genioplasty measurements made on cephalometric radiographs before and immediately after operation, and at least 6 months later. MAIN OUTCOME MEASURES: Comparison of horizontal and vertical measurements. RESULTS: In the screw (rigid) group mean horizontal advancement was 6.3 mm followed by a relapse of 0.3 mm during the follow up period. The corresponding figures for the wire (non-rigid) group were 5.8 and 0.5 mm. The two differed significantly in the degree of vertical change but the result is clinically unimportant. There was no difference in the degree of horizontal change. CONCLUSION: There was no difference in skeletal stability between the two groups.

Nasomaxillary osteotomy for the correction of Binder's syndrome (nasomaxillary dysplasia).

The treatment of Binder's syndrome, especially the reconstruction of the nose, has been challenging in the past. Although the Class III malocclusion can be corrected by a Le Fort I or II osteotomy, the rudimentary anterior nasal spine, the piriform rim, and the anterior maxilla remain retruded in relation to the rest of the maxilla and other facial structures. Nasal reconstruction based on this retruded potential anchor is difficult and probably the cause of unsatisfactory results. Surgical advancement of the nasal base by means of a nasomaxillary osteotomy not only simplifies the nasal reconstruction but also improves the esthetic results. The surgical technique is described and results are demonstrated by treated cases.

Surgical manipulation of the occlusal plane.

With combined surgical repositioning of the maxilla and the mandible, the occlusal plane is usually determined by the autorotation of the mandible. By manipulation of the cant of the maxillary occlusal plane, additional control of the esthetic result is obtained. In the approach discussed in this paper, prime attention is paid to repositioning of the maxilla into the most favorable situation by a deliberate rotation around points that are anterior in the face. The mandible is then surgically adjusted to secure a good occlusion. In this way, the cant of the occlusal plane becomes a priority in treatment planning, rather than simply an inevitable consequence of maxillomandibular surgery. The technique of treatment planning is discussed in detail, and three cases are presented to illustrate the concept. Of special importance is the enhancement of facial esthetics that is offered by the deliberate manipulation of the occlusal plane.

An alternative for the correction of the Class II low mandibular plane angle.

The traditional orthodontic and/or orthognathic surgical management of the Class II deep-bite case with a low mandibular plane angle has often been difficult; optimal esthetic results have not always been achieved, and long-term stability was often unpredictable. Many of these patients may benefit functionally and esthetically from appropriate orthodontic treatment and double-jaw surgical intervention to reorient the occlusal plane toward normal (8 degrees +/- 5 degrees to Frankfort horizontal) by moving the posterior maxilla and mandible superiorly and correcting into a Class I skeletal and occlusal relationship. As the occlusal plane angulation is increased, the upper incisor angulation decreases, the lower incisor angulation increases, the chin rotates down and backward relative to the lower incisor occlusal plane tips, and the mandibular plane angle increases. The principle of changing the occlusal plane has provided a means to improve the functional and esthetic results for the correction of this type of facial deformity, as well as many others.