Biomedical subjects

Karsten K H Gundlach

Publications and source records attributed to Karsten K H Gundlach.

12 recordsLinked to original sources

PubMed2006

Macroscopical, histological, and morphometric studies of porous bone-replacement materials in minipigs 8 months after implantation.

OBJECTIVE: The aim of this investigation was to test the induction of bone formation and biodegradation of different biomaterials based on calcium phosphate (CaP). Up to now, hydroxyapatite and beta-tricalcium phosphate ceramics have routinely been sintered at temperatures of 1300 degrees C. The new CaP biomaterials tested are fabricated by a sol-gel process at only 700 degrees C. STUDY DESIGN: Critical-size defects (>5 cm(3)) in the mandible of 15 adult Goettingen minipigs were filled with 1 of the 2 new types of CaP biomaterials, or with 1 of 2 well-known old-type ceramics, or with a gelatin sponge (in the control group). Macroscopical, histological, and morphometric examination of the former defect areas were made 8 months postoperatively. RESULTS: Eight months after implantation of the new CaP biomaterials, complete bone formation was observed in the defect area, and at the same time, the foreign material was resorbed almost completely. After implantation of the classical types of ceramics, only incomplete bone formation and a lesser resorption rate of the foreign bodies were noted. The difference in the bone formation rate was significant: more than 93% for the new CaP biomaterials versus less than 58% for the classical types of ceramics (P < 0.01). CONCLUSION: The biological behavior of the new CaP biomaterials was better than that of the old-type sintered ceramic bone-grafting materials. These new CaP matrices are suitable for filling bone defects and are of interest for dentists, including implantologists, craniomaxillofacial and orthopedic surgeons, as well as traumatologists.

Absorbable Implants↗

PubMed2006

Ossification of the frontal sinus in juvenile minipigs following water jet application.

BACKGROUND: Obliteration of the frontal sinus is a generally accepted management for patients with severe craniofacial trauma in whom the sinus cannot be repaired or adequately drained. Effective obliteration requires complete removal of mucosa, sufficient filling of the sinus cavity as well as effective occlusion of the nasofrontal duct. The use of various filling materials for sinus obliteration has been described and include autologous fat, bone, muscle and lyophilized cartilage. MATERIAL AND METHODS: In order to appreciate the advantages of the water-jet scalpel an animal study in 10 juvenile (4 months old) and 10 adult (18 months) minipigs was performed. In 5 juvenile and 5 adult animals the frontal sinus mucosa was removed using the water jet, while in the others bone curettes were used. No occlusion of the frontonasal duct was carried out and no filling material was implanted. All animals were followed-up for 40 days. After sacrifice, radiological, histological and computerized histomorphometrical examinations were carried out. RESULTS: Removal of the mucosa from the sinus was simplified when using the water jet. Previous studies have shown that the selected tissue structures were less traumatized when compared with conventional surgical techniques. In young animals (only) and exclusively following the use of a water-jet scalpel osseous occlusion of the frontal sinus was found at follow-up. Histomorphometric findings revealed a significant increase of bone formation in the frontal sinus area of these animals. CONCLUSION: Based on these experimental results in a small series of juvenile minipigs the water-jet technique is a faster and less traumatic technique (less blood loss) for osteoplastic surgery of the frontal sinus. Further long-term studies are needed to evaluate the possibilities for applying this technique in post-traumatic craniofacial surgery in man.

Animals↗

PubMed2006

Epidemiological studies on the frequency of clefts in Europe and world-wide.

BACKGROUND: Most textbooks present data on the various frequencies of clefts in different human "races". This was studied in more detail. MATERIAL AND METHODS: In a major literature study the frequencies of clefting reported in more than 100 publications were studied and the following data was collected: Incidences of clefts in Mongolians, Caucasians and Negroids; relative frequencies of clefts of the primary (and secondary) palate versus that of clefts of the secondary palate (only); data on cleft location (right, left, bilateral) and on genders affected. RESULTS: There was most confusing data on incidences in the different "races" whilst all other data was rather consistent: complete clefts (i.e. primary plus secondary palate affected) were most common with left sided ones being reported most often; males were more prone to have a cleft of the primary palate than females and females were more often affected by clefts of the secondary palate than males. DISCUSSION: The types of data bases having been evaluated varied from report to report indicating that today's data pools are of different qualities. Regional or national registries are necessary to collect reliable data with strict definitions applied in all countries.

Black People↗

PubMed2006

Presurgical orthopaedic treatment of newborns with clefts--functional treatment with long-term effects.

AIM: Presentation of an orthopaedic/orthodontic treatment protocol within the framework of complex rehabilitation of patients with clefts of lip, alveolus and palate. Presurgical orthopaedic treatment aims at reduction of cleft size by guiding growth and functional rehabilitation. Long-term results of maxillary development and occlusion at young adult age are reported. PATIENTS AND METHODS: 43 newborns with unilateral (19) or bilateral (24) clefts of lip, alveolus and palate were examined until their deciduous dentition was complete. In 29 patients a late follow-up was performed at age 17.3 years (mean). Maxillary dental casts were evaluated prior to and following presurgical orthopaedic treatment at the time the deciduous dentition was complete and at young adult age (2 to 5 years after termination of orthodontic treatment). Parameters were width of the alveolar and palatal cleft as well as width and length of the dental arch. In the adults occlusion was studied and the occlusal outcome was related to the therapeutical input. RESULTS: Presurgical orthopaedic treatment reduced the cleft width by taking advantage of normal growth. At the age of 3 to 4 years the development of the upper dental arch was in line with that of non-cleft children. CONCLUSION: Maxillary growth may be guided in almost physiological terms even in patients with a cleft of lip, alveolus and palate. Prerequisite is functional rehabilitation by means of orthopaedic treatment at age 1 to 12 months in terms of functional orthodontic therapy and a surgical protocol saving tissues with growth potential.

Adolescent↗

PubMed2005

Does avascular necrosis of the jaws in cancer patients only occur following treatment with bisphosphonates?

INTRODUCTION: In the last decade, bisphosphonates were regularly used to treat osteoporosis and bone pain from diseases such as metastatic breast cancer, multiple myeloma and Paget's disease. Currently, the influence of bisphosphonates in development of avascular osteonecrosis of the jaws has been recognized by various authors. In many cancer patients chemotherapy and medications like steroids have also to be applied. Agreement exists that these drugs can initiate vascular endothelial cell damage and accelerate disturbances in the microcirculation of the jaws possibly resulting in thrombosis of nutrient end arteries. The role of bisphosphonates in cancer patients with previously treated jaws has yet to be elucidated. PATIENTS: Four case reports of 'cancer' patients are described in whom osteonecrosis of the jaws was found. In two patients, the nitrogen-containing bisphosphonate zoledronic acid was prescribed for additional therapy of malignancy for a period of 45 up to 70 months. In another case, supportive treatment of breast cancer was offered using ibandronate. The fourth patient suffered avascular necrosis of the mandible without ever having taken bisphosphonates. In any case, revisional, as well as extended surgery has to be performed for osteonecrosis because neither conservative debridement nor antibiotic therapy have shown long term success, with or without bisphosphonates. No withdrawal of bisphosphonates was performed in view of the information on the direct correlation of total dosage and duration of drug intake to systemic incorporation and the long time for drug release. CONCLUSION: According to our observations, withdrawal of bisphosphonates is not recommended when necrosis of the jaws has occurred.

Adult↗

PubMed2005

Repair of bone defects by applying biomatrices with and without autologous osteoblasts.

QUESTION: Is it possible to stimulate osteoconduction and osteogenesis to improve bone formation in critical-size defects in order to avoid bone grafting? MATERIAL AND METHODS: Full thickness, critical-sized defects were created in the anterior mandible of 16 adult mini-pigs. The defects were filled with a new bioactive matrix (60% hydroxyapatite and 40% beta-tricalciumphosphate), produced by an innovative low temperature sol-gel-process (120 degrees C). The biomatrix was tested alone and in combination with cultured autologous osteoblasts. In a control group, periosteum was the only bone producing source. Five weeks postoperatively, the animals were sacrificed and the defects analysed macroscopically, histologically and radiographically. RESULTS: The highest rate of new bone formation was in the biomatrix group without osteoblasts (73% of the former defect). The biomatrix was degraded at the same speed as new bone was laid down. In the control group, bone formation of only 59% was observed. Additional transplantation of autologous osteoblasts in combination with the biomatrix did not result in more bone production than in the control group(!). CONCLUSION: This new bioactive calciumphosphate matrix seems to be a promising bone replacement material.

Animals↗

PubMed2005

Pneumosinus dilatans frontalis: two case reports.

INTRODUCTION: Pneumosinus dilatans was described first in 1898 by Meyes. Up to now only 60 cases have been published worldwide dealing mainly with young men between 20 and 30 years of age. The aetiology remains unknown. Whilst frontal sinuses are affected most often other sinuses can also be involved. The expansion of the pneumosinus is not only an aesthetic problem but may also have functional consequences. There may be a bulging of the roof of the orbit with consequent global displacement, ocular alterations and ptosis. Other features are headache and anosmia. PATIENTS: Two male patients with a pneumosinus dilatans of the frontal sinus are presented. They were 22 and 25 years old. The main complaints were aesthetic disfigurement. Treatment consisted of craniofacial repair of the malformation. RESULTS: While one patient was lost to follow-up, the other still is happy and has a stable aesthetic long-term result.

Adult↗

PubMed2005

Initial findings on teratological and developmental relationships and differences between neural tube defects and facial clefting. First experimental results.

Unless genetically caused, the occurrence of neural tube defects and clefts of the lip, alveolus and palate are not associated. These malformations do, however, share some common causes, one of which is folic acid deficiency. Nevertheless, it is not known why a neural tube defect resulting from folic acid deficiency does not occur in combination with facial clefts. Based on animal experiments and a review of the literature, it is assumed that other factors--such as vitamin B6 deficiency--though clinically not diagnosed, can more often cause malformations.

Alveolar Process↗

PubMed2003

Reconstruction of the frontal calvarian continuity in a child using a freeze-preserved autogenous bone graft.

Today, extended craniofacial defects in childhood can be treated by using modern techniques of bone banking and osteosynthesis, of particular importance when the restoration needs to consider calvarial growth. This is a report of an 8-year-old boy whose right frontal bone was removed during primary multidisciplinary trauma care. The bone was stored at a tissue bank using sterilization and freeze-dried preservation. Nine months later the graft was replaced and fixed with resorbable miniplates. Postoperatively no complications were observed and the (auto)graft has taken well. There was symmetrical craniofacial growth as well as a good aesthetic result three years after reconstruction.

Bone Transplantation↗

PubMed2003

Position of the hyoid bone in cleft lip, alveolus, and palate: variation of normal anatomy or sign accompanying the malformation?

OBJECTIVE: To compare the hyoid bone position in patients with clefts of lip, alveolus, and palate with orthodontic patients with no cleft. DESIGN: Retrospective cephalometric long-term study. PATIENTS: Lateral cephalograms of 23 patients with a complete unilateral cleft were compared with those of 24 orthodontic patients with no cleft with an Angle class 1 occlusion. Twenty-five of the patients were girls, and 22 were boys. The age of the patients with cleft at the beginning of the study was 8.1 +/- 0.7 years and at the end 14.8 +/- 0.6 years. The patients without cleft were 8.4 +/- 0.8 years old at the beginning and 14.4 +/- 0.6 years at the end of the study. MAIN OUTCOME MEASURES: Cephalometric analysis was used to determine the skull growth pattern as well as the positions of the head and hyoid bone twice in all 47 persons. RESULTS: With increasing age of the patients, the skull growth pattern changed from vertical to horizontal growth, but no significant differences were found between patients with and without cleft. Head position did not differ significantly between patients with and without cleft. However, hyoid bone position differed significantly. The hyoid in patients with cleft was located more caudally and more anteriorly than in patients without cleft. CONCLUSION: The hyoid bone in a subset of north German adolescents with complete unilateral cleft lip and palate was found to be caudal and anterior, compared with a control group.

Adolescent↗

PubMed2002

Blood supply of the mandibular cortex: an experimental study in Göttingen minipigs with special reference to the condyle.

INTRODUCTION: Blood supply of the mandible is an important factor that influences bone growth and bone repair. MATERIAL AND METHODS: An experimental study was carried out in 24 mandibles of 12 Göttingen minipigs to study the blood supply of the mandibular cortex. RESULTS: Endosteal blood supply prevails in the cranial part of the mandible including the condyle, whilst periosteal blood supply predominates in the caudal part of the mandible, the body. The two forms of blood supply are in balance in the ascending ramus and the angle of the mandible. CONCLUSION: The mandibular cortex can be divided into three parts, each having different sources of blood supply. The results of this study may be of significance for man and could help to understand some pathological disorders of the mandible.

Animals↗

PubMed2002

Experimental and comparative study of the blood supply to the mandibular cortex in Göttingen minipigs and in man.

INTRODUCTION: Since the blood supply to the mandibular cortex is an important factor for bone growth and bone repair, experimental studies on the blood supply in animal models (such as Göttingen minipigs) applicable to man are necessary. Their value depends on the requirement that the patterns of blood supply in the two species are similar. MATERIAL AND METHODS: Twelve Göttingen minipig mandibles (24 halves) and four human mandibles (eight halves) were investigated for the blood supply to the mandibular cortex. RESULTS: Only minor differences were found in blood supply to the mandibular cortex between the two species. Common to both was: in the cranial part of the mandible (including the condyle), the endosteal blood supply prevailed, whereas the periosteal blood supply predominated in the caudal part of the mandible (the body). Both patterns of blood supply were in balance in the centre section, i.e. angle and ascending ramus of the mandible. CONCLUSION: The present study confirms that results obtained from Göttingen minipigs, used as an experimental animal model, are applicable to man: three different types of blood supply are evident in the mandibular cortex in both species.

Animals↗