Rudolf Mossböck

Assessment of Bone Resorption After Secondary Alveolar Bone Grafting Using Three-Dimensional Computed Tomography: A Three-Year Study

Objective: Secondary bone grafting plays an important role in the dental rehabilitation of patients with clefts of the lip, alveolus, and palate. A major complication of this surgical technique is resorption of the grafted bone transplant. Conventional two-dimensional radiographs are often inconclusive and do not demonstrate the true deficit. The main objective of this study was to evaluate the amount and exact location of bone loss on the basis of three-dimensional models over a period of 3 years. Design: Twenty-four patients with unilateral cleft palate were included in this prospective study. Axial computed tomography scans of all patients were taken immediately preoperatively, and 1, 2, and 3 years postoperatively. Volumetric analysis was performed on three-dimensional models of the cleft defects and the bone bridges using three-dimensional computed tomography. Interventions: All patients were treated by secondary alveolar bone grafting prior to eruption of the permanent canine. Results: Extensive bone resorption was found in the bucco-palatal dimension of the alveolar portion of the transplant. The success rate of secondary bone grafting was high in cases of rapid orthodontic gap closures. The mean bone loss in the first year after surgery was 49.5%. The transplants remained almost constant in the following 2 years. Conclusions: Radiographic scales based on orthopantomography only evaluate the vertical dimension of the transplants. This study, however, showed that bone resorption in the transversal dimension is clearly underestimated with conventional two-dimensional radiographs.

Three-dimensional evaluation of secondary alveolar bone grafting using a 3D- navigation system based on computed tomography: a two-year follow-up.

Secondary bone grafting is widely used in the closure of oronasal fistulas and reconstruction of maxillary defects. It often fails from lack of physiological stress or inadequate covering of the transplanted bone with surrounding tissue. The aim of this study was to assess the exact bone volume after secondary alveolar bone grafting over a period of two years using a navigation system based on computed tomography (CT). We examined 20 patients with complete unilateral cleft lip and palate (UCLP) who had been treated by secondary bone grafting during late mixed dentition. CT scans of the upper jaw were taken immediately preoperatively, and 1 and 2 years postoperatively. The cleft defects and the bony bridges were marked on the monitor. The software of the navigation system created three-dimensional models showing the amount and site of bone resorption. The mean bone loss after one and two years was 51% and 52%, respectively. There was a significant correlation between the size of the cleft and the success of the alveolar bone grafting (p=0.01). When the teeth adjacent to the cleft were missing the amount of bone lost was 95% after the first year. There was also significant bone loss in the buccopalatine direction. Three-dimensional reconstruction of the bony bridges with a navigation system accurately shows the amount of bone within the cleft site. This method is definitely superior to conventional two-dimensional orthopantomography.

Cephalometric and occlusal outcome in adults with unilateral cleft lip, palate, and alveolus after two different surgical techniques

OBJECTIVE To assess differences in the aesthetic and functional long-term results of one-stage and two-stage surgical and orthodontic treatment in patients with cleft lip, palate, and alveolus. DESIGN Sixty adult patients who were operated on as children for unilateral cleft lip, palate, and alveolus were examined. In every patient the lip was closed using Tennisons technique. Thirty patients had soft and hard palate closure in two stages and 30 patients in a single stage. Lateral cephalometric and model analyses were conducted at a mean age of 18.4 years. RESULTS In the model analysis, transverse narrowing was seen in all patients after two-stage operations and in three patients after one-stage operations. The deficit was more severe in the molar region in the two-stage group and nearly similar in the premolar and molar region in the one-stage group. A sagittal deficiency in the anterior maxilla was found in 26 patients after two-stage operations and in 16 patients after one-stage operations. In the lateral cephalometric analysis, the mean sella-nasion-point A angle in the one- and two-stage group was 78.2 degrees and 76.8 degrees, respectively. The ANB angle was normal in both groups. In both groups the inclination of the midface was low. There was a low posterior facial height. Minor scarring was seen in the single-stage group. CONCLUSION A more severe impairment of growth of the maxilla in the sagittal and frontal plane was observed after two-stage operations on the cleft palate.

Differences in cephalometric and occlusal outcome of cleft palate patients regarding different surgical techniques

INTRODUCTION The purpose of this study was to assess differences of the long-term results following surgical treatment in patients with cleft palate treated by two different surgical concepts. PATIENTS Fifty-nine adult patients operated on for cleft palate were examined. Thirty palates were closed by a two stage (Widmaier and Veau) and 29 by a single-stage procedure (Veaus pedicled flap). METHODS Lateral cephalometric and model analysis was performed. In the cephalometric analysis, the vertical and horizontal parameters of the position of maxilla and midface and transverse and sagittal dimensions of the models were compared between the two groups. RESULTS Model analysis: According to the Bolton analysis the maxillary dental arch was too large in 22 patients in each group. The other patients had mandibular arches that were too large. In 18 patients with two-stage closure and in 9 patients with one-stage closure, a space deficit in the lateral part of the maxilla was observed. Persisting transverse deficits were seen in all patients with two-stage repairs and in 11 patients with one-stage repairs. The deficit was more severe in the molar area in the first group and almost equally severe in the premolar and the molar regions of the second group. A sagittal deficiency was found more often in patients with two-stage repairs while Angles class I occlusion was seen more often in patients with one-stage surgery. Lateral cephalometry: Similar SNA-angles were seen in both groups whereas the ANB-angle was greater following two-stage repair. In both patient groups a low inclination of the midface was seen. The vertical dimension of the midface in comparison with the lower face was normal in the one-stage group; in the other group a deficiency of the anterior midface height was registered. CONCLUSION There was a more severe growth impairment of the midface in patients with this type of two-stage palatal repair. The horizontal deficiency was similar in both groups. The long-term occlusal result revealed smaller sagittal and transverse deficiencies in patients with this type of single-stage closure.

Advantage of Three-Dimensional Models in Intraoral Callus Distraction

Distraction osteogenesis has become an important method of reconstructing hypoplastic facial bones. Intraoral callus distraction is a great aesthetic improvement, because no visible scars are caused. Precise preoperative planning is necessary, however, because the direction of distraction cannot be influenced postoperatively. Nine three-dimensional (3-D) models were used in three intraoral distraction cases: two patients suffered from unilateral hemifacial microsomia and one from micrognathia after bilateral ankylosis caused by multifocal osteomyelitis in childhood. In each case, models of the head were produced and the distraction was simulated preoperatively. The amount of distraction was 18 mm in the two hemifacial microsomia patients and 18 and 14 mm in the ankylosis case. Extension of distraction in the ankylosis patient was shorter on one side in order to achieve a correct midline position. A slight overcorrection of 3-5 mm was allowed to cover relapse and unpredictable future growth deficiency. Three-dimensional models can supply important information when employed in intraoral callus distraction. They allow anticipation of pitfalls and help to achieve a foreseeable result. Further advantages may be expected with complete 3-D enoral distraction in the future.

Simultane Orbitaexpansion und Kallusdistraktion von Ober- und Unterkiefer bei einem Goldenhar-Patienten

ZusammenfassungDie Korrektur des Minderwuchses der Orbita, bedingt durch Anophthalmus oder Mikrophthalmus, stellt eine therapeutische Herausforderung dar. Beim Goldenha-Syndrom ist er durch eine zusätzliche Wachstums-störung des Jochbeins und des Unterkiefers kompliziert.Es wird der Fall eines 5-jährigen Patienten mit Goldenhar-Syndrom beschrieben. Nach exakter dreidimensionaler Operationssimulation am 3D-Modell wurde zur Korrektur der Jochbeinhypoplasie und des Oberkieferschiefstandes eine Distraktionsosteoneogenese mit einem enoralen Kallusdistraktor im Oberkiefer durchgeführt. In der selben Sitzung wurde der aufsteigende Unterkieferast distrahiert und in die Orbita ein Gewebeexpander eingesetzt.Durch diese Therapie konnte der Jochbeinkomplex sowie Oberkiefer und Unterkiefer symmetrisch positioniert bzw. verlängert werden. Die Orbita wurde auf 75% der gesunden Seite erweitert. Nach fünf Monaten wurden die Distraktoren entfernt und der Gewebeexpander gegen einen größeren getauscht, um eine Überexpansion der Orbita zu erzielen.Mit Hilfe der von Rodallec et al. 1988 beschriebenen Methode ist eine Orbitaexpansion möglich. Enorale, subperiostal plazierte Kallusdistraktoren ermöglichen Knochen-„wachstum“ ohne aufwendige Transplantation. Durch die Kombination beider Methoden können jetzt auch komplexe Fehlbildungen in einer Sitzung korrigiert werden.SummaryCorrection of micro-orbits, caused by anophtalmia or severe microphtalmia is a very challenching task. In Goldenhar syndrome it is combined with hypoplasia of malar bone and ascending mandibular ramus.A case of a 5-year old patient with Goldenhar syndrome is described. After precise simulation surgery on a 3D-model, hypoplasia of the malar bone and the oblique maxilla was corrected by means of enoral distraction osteogenesis in the upper jaw. In the same operation the ascending ramus of the mandible was lengthened with a second distraction device and a tissue expander was inserted into the orbit.Due to this therapy the malar bone as well as upper and lower jaw could be lengthened and thereby positioned symmetrically. The orbital cavity was expanded to 75 percent of the contralateral side. Five month after the first operation the expander was changed against a larger one to achieve an overcorrection of the orbit.Orbital expansion by means of the technique described by Rodallec et al. in 1988 is possible. Enoral subperiosteal placed distraction devices enable bone „growth“ making bone transplants unnecessary. By combining both methods even complex malformations can be corrected in one session.