Experimental model for transplantation of a modified free myocutaneous gracilis flap to an irradiated neck region in rats.

In 102 Wistar rats (male, weight 300-500 g), a modified free myocutaneous gracilis flap was obtained from the groin and transplanted to the neck. To create a pre-irradiated transplant bed, a local area of the neck was irradiated preoperatively with 30 Gy (fractionation: 3 x 10 Gy) in 30 animals, and with 50 Gy (fractionation: 5 x 10 Gy) in a further 30 animals. The interval between preoperative irradiation and transplantation was 4 weeks.

A prospective electromyographic and computer-aided thermal sensitivity assessment of nerve lesions after sagittal split osteotomy and Le Fort I osteotomy.

Purpose: The purpose of this study was to determine the incidence of temporary and permanent sensory disturbance of the inferior alveolar nerve (IAN) after bilateral sagittal split osteotomy (BSSO) of the mandible and of the infraorbital nerve (ION) after Le Fort I osteotomy, as well as the rate of recovery of sensory function using subjective and objective measures.

Patients And Methods: Preoperatively and after 1 week, and 1, 3, 6, and 12 months postoperatively, sensibility in the distribution of 36 IONs after Le Fort I osteotomy and 24 IANs after BSSO in 19 patients were investigated by using sharp-blunt testing, 2-point discrimination, electromyographic recording, and thermal sensitivity (Pain and Thermal Sensitivity Test Device [PATH]) tests of the Adelta and C nerve fibers.

Results: With conventional clinical sharp-blunt and 2-point discrimination tests, the incidence of temporary impairment was 81% for the ION (29 of 36) and 83% for the IAN (20 of 24).

Distraction osteogenesis of the maxilla and midface using a subcutaneous device: report of four cases.

The use of distraction osteogenesis in the hypoplastic maxilla and midface is still controversial. Since the beginning of 1998, 25 patients have been treated with osteodistraction techniques for various reasons. Among them were four patients who were treated by high LeFort I osteotomies and insertion of a newly developed subcutaneous distraction device in the malar region.

Continuous and intermittent bone distraction using a microhydraulic cylinder: an experimental study in minipigs.

Distraction osteogenesis of the mandible is an option in the treatment of mandibular hypoplasia. Today, only intermittent distraction devices are available for clinical application. The aim of this study in minipigs was to evaluate continuous bone distraction using a microhydraulic cylinder.

[Possibilities of computer graphics simulation in orthopedic surgery].

Background: In addition to standard X-rays, photographic documentation, cephalometric and model analysis, a computer-aided, three-dimensional (3D) simulation system has been developed in close cooperation with the Institute of Communications of the Friedrich-Alexander-Universität Erlangen-Nürnberg. With this simulation system a photorealistic prediction of the expected soft tissue changes can be made. Prerequisites are a 3D reconstruction of the facial skeleton and a 3D laser scan of the face.

[Vascularization of free myocutaneous gracilis flaps in replacement transplantation after preoperative radiotherapy. An experimental study].

Background: Following preoperative radiotherapy prior to ablative surgery of squamous epithelial carcinomas of the head and neck region, inflammatory changes to the connective tissue and vascular endothelium are observed. These processes may lead to a delay in healing of free flaps in the irradiated transplant bed. The aim of the study was to investigate qualitative and quantitative changes in vascularization in irradiated and regular transplant beds.

Soft tissue profile changes after autogenous iliac crest onlay grafting for the extremely atrophic maxilla.

Purpose: The aim of this study was to evaluate profile changes in the hard and soft tissues after onlay grafting in the extremely atrophic maxilla.

Patients And Methods: Onlay grafting using autogenous iliac crest bone grafts was performed in 49 patients (42 females and 7 males) with extreme atrophy of the edentulous maxilla (vertical amount of bone: <6 mm, transverse amount of bone: <5 mm). For the assessment of the changes to the hard and soft tissues, the preoperative and postoperative cephalograms were traced and the cephalometric measuring points (44 skeletal and 25 soft tissue points) were digitalized with the aid of the Dentofacial Planner System.

[Implantology].

Endosseous osseointegrated implants have become an integral part of the treatment scheme for the prosthetic reconstruction and rehabilitation of masticatory function following scientific studies of the reactions between implant and soft and hard tissues. Furthermore, implants offer good chances for prosthetic rehabilitation in the insufficient bone site, if the extremely atrophic jaw is to be reconstructed by grafting procedures with avascular and vascular grafts, by guided bone regeneration, by distraction osteogenesis, by bone substitutes and in the future by osteoinductive proteins in order to prepare the conditions for implant insertion. Those reconstruction procedures combined with implants become often necessary, if complicated hard and soft tissue defects of the skull have to be reconstructed to create the prerequisites for the stabilisation of epitheses or to insert implant-supported devices.

[Distraction osteogenesis of the mandible in craniofacial abnormalities].

In recent years, lengthening the human mandible by distraction osteogenesis has become an accepted treatment to correct severe mandibular hypoplasia. Using intraoral unidirectional and extraoral bidirectional distraction devices we report about our experiences and results in the application of the bone distraction technique in four selected cases of syndromal disease, including various forms of mandibular hypoplastic malformations. The patients involved were a boy with Pierre Robin syndrome, a girl with unilateral facial hypoplasia in Goldenhar's syndrome, a case with Nager's syndrome, and a rare case of midline deficiency caused by partial deletion of chromosome 18 (18p-syndrome).

A new distraction device to compare continuous and discontinuous bone distraction in mini-pigs: a preliminary report.

Callus-distraction has become an accepted procedure to lengthen hypoplastic mandibles in humans. Extra- and intraoral devices have been applied successfully. Systematic studies have proven the importance of direction, stability, rate and frequency in callus-distraction.

Histomorphometric analysis of irradiated recipient vessels and transplant vessels of free flaps in patients undergoing reconstruction after ablative surgery.

The aim of the study was to investigate, histomorphometrically, quantitative and qualitative changes in irradiated neck recipient vessels and transplant vessels used for microsurgical anastomoses in free flaps in patients undergoing preoperative radiotherapy and chemotherapy. In 55 patients receiving 42 radial forearm flaps, 6 latissimus dorsi flaps, 6 osteomyocutaneous fibula grafts and 1 lateral arm flap, a total of 220 vessels were obtained from neck recipient vessels and transplant vessels during anastomosis. Three groups were formed: Group 1 (16 patients) treated with no radiotherapy or chemotherapy; Group 2 (20 patients) treated with preoperative irradiation (40-50 Gy) and chemotherapy (800 mg/m2 5-FU and 20 mg/m2 cisplatin) 1.

[Continuous bone distraction with the help of a microhydraulic cylinder].

Distraction osteogenesis of the mandible is one treatment option in mandibular hypoplasia. Usually, a non-continuous distraction mode is applied. The aim of the present study was to establish continuous bone distraction using a microhydraulic cylinder.

Osseointegration of endodontic endosseous cones: zirconium oxide vs titanium.

Objective: The purpose of this investigation was to investigate the osseointegration of zirconium oxide (ZrO(2)) ceramic cones in comparison with that of titanium cones in apicectomy.

Study Design: To evaluate the bone/implant interface, 20 ZrO(2) cones and 20 titanium cones were inserted into the mandibles of 4 Göttinger minipigs. During the 6-month healing period, intravital polychrome sequence marking was performed.

Long-term results of endosteal implants used for restoration of oral function after oncologic surgery.

The aim of the present study was to analyse the long-term survival rate of endosteal implants used for restoration of oral function in patients having undergone oncologic surgery. Eighty-three consecutive patients, who had received a total of 409 endosteal implants ad modum Brånemark, subsequent to resections of soft tissue and bone during ablation of oral malignancies, were enrolled into the study. A life-table analysis was used to determine the survival rate of the implants placed during a period of 13 years.

[Masticatory rehabilitation of tumor patients by endosseous implants. 10 year analysis].

A total of 409 implants was inserted into 83 consecutive patients, who had tumor-related intraoral resections of soft tissue and bone. A life table analysis was used to determine the survival rate of the implants placed over a period of 13 years. Log rank tests and a Cox regression analysis were employed to identify relevant effects of surgical parameters on implant survival.

Prospective study on post-traumatic and postoperative sensory disturbances of the inferior alveolar nerve and infraorbital nerve in mandibular and midfacial fractures.

In a prospective study (January 1999 to December 1997), 34 patients with 26 mandibular and 20 midfacial fractures were investigated. All the fractures were managed by osteosynthesis. To evaluate the incidence and duration of recovery of post-traumatic and postoperative sensory disturbances, the following tests were carried out: sharp/blunt testing, and the two-point discrimination test as conventional clinical examination methods, and electromyographic recording of the masseter reflex to calibrate the clinical findings.

Survival analysis of endosseous implants in bone grafts used for the treatment of severe alveolar ridge atrophy.

Purpose: The aim of the current study was to evaluate the long-term results of endosseous implants placed into autogenous bone grafts in severely atrophic alveolar ridges.

Patients And Methods: A total of 871 implants were placed in 137 patients. The success rate was determined using survival analysis, log rank tests, and a cox regression analysis.

[Profile modification of the middle and lower face after anterior onlay osteoplasty in severe atrophy of the maxilla].

A retrospective study was performed to evaluate hard- and soft-tissue changes after onlay bone grafts in atrophic maxillae. The assessment included 49 patients who received bone grafts from the iliac crest. Lateral cephalograms were taken pre- and postoperatively and analyzed by the Dentofacial Planner System.

Use of sequential bone scintigraphy for monitoring onlay grafts to grossly atrophic jaws.

Objectives: To evaluate the capability of sequential bone scintigraphy for assessing the viability of avascular onlay grafts in combination with primary or secondary implant placement.

Methods: Forty-six patients with severe alveolar ridge atrophy received full-arch onlay grafts from the iliac crest. Twenty patients received primary insertion of endosseous implants, while secondary implant placement was performed in 26 patients after an average interval of 95 days.

[Bone SPECT of the jaws after fracture, onlay osteoplasty of insertion of implants].

Aim: The aim of this study was early differentiation between uncomplicated and complicated processes of healing in the jaw using bone SPECT.

Methods: Investigations were performed in 40 mandibular fractures and 26 jaws after onlay osteoplasty as well as secondary insertion of implants. Bone SPECT was carried out within 1-2 months and after approximately 4-5 months.

[Reconstruction of speech and chewing function after extensive tumor resection in the area of the jaw and face].

Background: Following extensive resections of head and neck tumors, re-establishing speech and masticatory function are of crucial importance for the patient.

Methods: In 23 patients with vascularised jejunal grafts for reconstruction of the intraoral mucosa, tongue and floor of mouth, a speech intelligibility test was performed, tongue and floor of mouth mobility was investigated using a 3.5 MHz ultrasound scanner.

Postoperative function after implant insertion in vascularized bone grafts in maxilla and mandible.

Between 1988 and 1992, 80 Brånemark-type implants were inserted in 18 patients during reconstruction of the mandible or maxilla with vascularized iliac crest or scapula grafts with or without additional soft tissue pedicles. In these procedures, nine vascularized bone grafts were combined with a primary insertion of 32 implants and a secondary insertion of 48 implants. Twelve patients are currently wearing the implant-borne dentures.

Masticatory function of postoperative tumor patients rehabilitated with osseointegrated implants.

Purpose: This study determined the level of masticatory function that can be achieved with osseointegrated implants in postoperative tumor patients.

Patients And Methods: Masticatory function was evaluated in 15 postoperative tumor patients with implants, 22 nontumor patients with implants, and 15 natural dentate controls. The area of occlusal contact was evaluated with a pressure-sensitive, color-developing bite sheet analyzed by computer.

The free revascularized rectus abdominis myocutaneous flap for the repair of tumour related defects in the head and neck area.

The present work reviews a series of 11 consecutive patients who have received free revascularized rectus abdominis myocutaneous flaps for primary reconstruction of soft tissues after ablative tumour surgery in the head and neck area. In 10 patients, a total or subtotal glossectomy had been performed and the flap was used to replace the resected tongue volume. In 5 of these cases, extensive perforating defects had resulted after additional resection of large portions of the chin and the cheek.

A computerized method for evaluating distribution of occlusal load on implant-supported fixed cantilever prostheses.

An investigation was conducted to determine whether Dental Prescale, a material that undergoes a graded color-producing chemical reaction when force is applied, could be used to evaluate occlusal load distribution objectively and quantitatively when combined with computer analysis. Ten patients with an implant-supported fixed cantilever prosthesis and a complete conventional maxillary denture were studied. The results indicated that the system can be used to evaluate occlusal load distribution with sufficient reproducibility.