Tomas Gedrange

Ectopic bone formation in nude rats using human osteoblasts seeded poly(3)hydroxybutyrate embroidery and hydroxyapatite-collagen tapes constructs

PURPOSE The aim of this study was to evaluate the ectopic bone formation using tissue engineered cell-seeded constructs with two different scaffolds and primary human maxillary osteoblasts in nude rats over an implantation period of up to 96 days. MATERIAL AND METHODS Collagen I-coated Poly(3)hydroxybutyrate (PHB) embroidery and hydroxyapatite (HAP) collagen tapes were seeded with primary human maxillary osteoblasts (hOB) and implanted into athymic rnu/run rats. A total of 72 implants were placed into the back muscles of 18 rats. 24, 48 and 96 days after implantation, histological and histomorphometric analyses were made. The osteoblastic character of the cells was confirmed by immunocytochemistry and RT-PCR for osteocalcin. RESULTS Histological analysis demonstrated that all cell-seeded constructs induced ectopic bone formation after 24, 48 and 96 days of implantation. There was more mineralized tissue in PHB constructs than in HAP-collagen tapes (at day 24; p < 0.05). Bone formation decreased with the increasing length of the implantation period. Osteocalcin expression verified the osteoblastic character of the cell-seeded constructs after implantation time. No bone formation and no osteocalcin expression were found in the control groups. CONCLUSIONS Cell-seeded constructs either with PHB embroidery or HAP-collagen tapes can induce ectopic bone formation. However, the amount of bone formed decreased with increasing length of implantation.

Experimental and histological investigations of the bone using two different Oscillating Osteotomy techniques compared with conventional rotary osteotomy

Over the past decade, coinciding with the appearance of a number of new ultrasonic surgical devices, there has been a marked increase in interest in the use of ultrasound in oral surgery and implantology as alternative osteotomy method. The aim of this study was the comparison of the effect of osteotomies performed using ultrasonic surgery (Piezosurgery(®)), sonic surgery SONICflex(®) and the conventional bur method on the heat generation within the bone underneath the osteotomy and light-microscopy observations of the bone at different cutting positions in porcine mandibular segments. It was found that the average heat generated by SONICflex(®) sonic device was close to that by conventional rotary bur (1.54-2.29°C), whereas Piezosurgery(®) showed a high generated heat up to 18.17°C. Histological investigations of the bone matrix adjacent to the defect radius showed intact osteocytes with all three instruments and similar wide damage diameter at the bottom region. SONICflex(®) showed smooth cutting surfaces with minimal damage in the upper defect zone. Finally, presented results showed that sonic surgery performed with SONICflex(®) is an alternative osteotomy method and can be used as an alternative to the conventional bur method.

Cranial base features in skeletal Class III patients.

OBJECTIVE To investigate the cranial base configuration in skeletal Class III patients to clarify the conflicting findings from literature. MATERIALS AND METHODS Initial lateral radiographs of 54 skeletal Class III patients and 54 matched controls (Class I, II/1, II/2) aged 14 to 24 years were analyzed retrospectively for 21 cephalometric basicranial variables and jaw lengths relative to anterior cranial base length. RESULTS In contrast to overall cranial base length, the anterior (N-S) and posterior (S-Ba, S-Ar) sections failed to show a significant reduction in Class III patients. The significantly more acute angles Ca-S-Ba and Se-S-Ba reflected increased cranial base flexure. Resulting anterior condylar displacement was shown by significant reduction of Se-S-Cd and Ar-Ca. Relative mandibular length was significantly increased. CONCLUSIONS Decreased basicranial angulation associated with Class III mandibular protrusion was clearly confirmed for skeletal Class III patients. Overall shortening of the cranial base apparently resulted from various minor alterations. The results are compatible with the deficient orthocephalization hypothesis of Class III morphogenesis. The basicranial-maxillary relationship in skeletal Class III remains unclear.

Evaluation of bone availability in the cleft area following secondary osteoplasty

INTRODUCTION Osteoplasty in cleft patients provides a basis for shaping a closed dental arch. This study aimed at a radiological appraisal of transplantation success following secondary osteoplasty by means of alveolar bone height as related to some selected influencing factors. MATERIAL AND METHODS In this study, postoperative radiographs of 46 patients with unilateral or bilateral clefts of lip, alveolus and palate were analyzed retrospectively. Alveolar bone height was typed according to Abyholm and Bergland and evaluated in consideration of dentition at the time of surgery and existence of the lateral incisor. RESULTS In total, 76% (n = 35) successes (type I/II) were observed. 6 out of 46 patients (13%) had to be re-operated for osteoplasty at a later date. A non-significantly higher rate of successes occurred during the early mixed dentition. In patients with existing lateral incisor, a higher rate (78% vs. 68%) of alveolar bone heights type I/II was obtained. CONCLUSION The successful surgical outcome in terms of alveolar bone height is facilitated by treatment onset preferably during early mixed dentition and in presence of the lateral incisor. Although maximal success rates cannot be obtained using this method, the utility and effectiveness of secondary osteoplasty in cleft patients has been confirmed.

Functional 3-D analysis of patients with unilateral cleft of lip, alveolus and palate (UCLAP) following lip repair.

INTRODUCTION Particular importance is attached to lip repair cleft surgery, as numerous functional and aesthetic aspects have to be taken into account simultaneously. Spatial assessment of function and depiction of dynamic deviations is reasonable for describing surgical outcome in addition to long standing static analysis. This study aimed at 3D analysis of the oral area after reconstruction in patients with unilateral cleft lip, alveolus and palate. PATIENTS AND METHODS Twelve patients with unilateral cleft lip, alveolus and palate who underwent surgery according to Tennison-Randall were enrolled in this study. Soft tissue dynamics was analysed during passive stretching and active contraction of the lips, and photogrammetry was used for comparing relative changes of length and displacement vectors. The spatial coordinates of surgically significant and reproducible landmarks along the red-white lip junction were analyzed. RESULTS Static analysis of the lips revealed a good result with far-reaching symmetry in all cases. Regarding dynamic behaviour, two groups could be distinguished showing clear differences of passive distension and contraction behaviour. CONCLUSION Despite nominally identical surgical techniques and comparable static-morphological outcomes, dynamic analysis revealed differences pointing to a need for optimization.

In vivo study of apoptosis as a creative agent of embryonic development of the primary nasal duct in rats

INTRODUCTION The first embryonic part of the nasal cavity is the primary nasal duct, beginning with the olfactory placode and ending with the oronasal membrane. Aim of this study was to investigate the cellular processes (apoptosis, proliferation) being responsible for development and opening of the primary nasal duct. MATERIAL AND METHODS In this study developmental processes in at least three regions of the primary nasal duct (opening, middle, end) were examined by sectioning 38 rat fetuses on day 13.5 after conception. Apoptotic cells were detected by active caspase-3 antibodies and proliferating cells were examined by Ki-67 antibodies. RESULTS Multiple apoptotic events were diagnosed on the basis and proliferative cells on the top of this duct. CONCLUSION Apoptosis and proliferation play an important role in the process of opening the bottom of the primary nasal duct and for development of the nasal septum, philtrum as well as the primary palate. Mesenchymal proliferation seems to play a minor role in the process of opening the primary nasal duct.

Conventionally ligated versus self-ligating metal brackets—a comparative study

The purpose of this study was to compare the frictional properties of four self-ligating metal brackets, Speed, Damon 2, In-Ovation, and Time, with those of three conventionally ligated metal brackets, Time, Victory Twin, and Discovery. The self-ligating Time bracket can also be used as a conventionally ligated bracket. Friction was tested 20 times for each bracket/wire combination using a Zwick testing machine with stainless steel wires in three different wire dimensions (0.017 x 0.025, 0.018 x 0.025, and 0.019 x 0.025 inches). All brackets had a 0.022 inch slot and the prescription of an upper first premolar. The data were statistically analysed with unsigned comparisons of all bracket/wire combinations using the Mann-Whitney U-test and the Games-Howell post hoc test. The results showed almost all brackets to have the lowest frictional force with a wire dimension of 0.018 x 0.025 inch. Friction of the self-ligating brackets using wire with a dimension of 0.018 x 0.025 inches was 45-48 per cent lower than with 0.017 x 0.025 and 0.019 x 0.025 inch wires. Friction of the conventionally ligated brackets showed a 14 per cent or less reduced friction with 0.018 x 0.025 inch wire compared with 0.017 x 0.025 and 0.019 x 0.025 inch wires. The self-ligating metal brackets showed lower frictional forces with a 0.018 x 0.025 inch wire than conventionally ligated brackets, whereas conventionally ligated brackets showed lower friction with 0.017 x 0.025 and 0.019 x 0.025 inch wire. Friction values vary with different bracket/archwire combinations and, therefore, the choice of a bracket system for treatment should consider the correct wire dimension to produce the lowest possible frictional forces.

Presurgical nasoalveolar molding in patients with unilateral clefts of lip, alveolus and palate. Case study and review of the literature

INTRODUCTION The case of a newborn female patient with unilateral cleft lip, alveolus and palate is presented with a markedly sunken nasal wing at the cleft side. This finding may lead to a very unsatisfactory aesthetic result after primary cheiloplasty and nasoplasty. PATIENT AND METHOD Five months prior to surgery, the patient was treated with a palatal plate and additionally with a nasoalveolar conformer for 4 months thereof. The device consisted of an acrylic pelotte (attached to the maxillary plate with a wire) which lifted the nasal dome and was activated regularly. Under this presurgical treatment, the cleft edges moved closer to each other by 1.8 mm at the alveolar ridge and by 4.5 mm in the palatal area. The nasal wing was lifted by 5 mm. This was enabling elevation of the nasal wing during primary surgery in the case described. Questions are raised as to the remaining effects on nasal symmetry until completion of growth and, on the other hand, as to the chances to reduce postsurgical alar relapse by continued nasal molding beyond primary surgery. CONCLUSION Presurgical nasal molding seems to improve aesthetics of the nose in patients with unilateral clefts of lip, alveolus and palate and distinctly flattend nasal wings.

Apoptosis as a creative agent of embryonic development of bucca, mentum and nasolacrimal duct. An in vivo study in rats.

INTRODUCTION For embryonal facial development several fusion processes between different facial prominences are necessary. If fusion fails to appear, various facial clefts may occur, known as median (e.g. lower median cleft lip), oblique (e.g. open nasolacrimal duct) or lateral facial clefts (macrostomia, lateral cleft). MATERIAL AND METHODS The development of 3 different facial regions (bucca, mentum, and nasolacrimal duct) was examined in rats using serial histological sections on day 13.5 after conception. Common procedures were used (staining for active caspase-3 and for Ki-67) for histological assessment about the role of apoptotic and proliferative processes in the fusion zones of buccal, mental and nasolacrimal areas. RESULTS Multiple apoptotic events were detected in epithelial cells of the respective regions, the proliferative centers were located in the mesenchymal surroundings of fusion zones. CONCLUSION A substantial precondition for fusion of facial prominences are proliferative and apoptotic processes in epithelial and mesenchymal cells. Apoptosis contributes to the development of bucca, mentum and the nasolacrimal duct. Absence of apoptoses may be responsible for facial clefts.

Maxillary sinus pneumatization of an adult skull with an untreated bilateral cleft palate

INTRODUCTION Patients with clefts of lip, alveolus and palate show a high incidence of maxillary sinusitis. In order to evaluate sinus size as a factor in sinusitis, this study investigates maxillary sinus morphology in an adult skull with an untreated bilateral cleft. MATERIAL AND METHODS The maxillary sinus volume (MSV) of a mixed-sex sample of 140 adult skulls from three different populations was assessed and compared with the MSV of a skull of a 25 year old man showing an untreated complete bilateral cleft. A least squares regression analysis was used to investigate the relationship between MSV and different external cranial dimensions. RESULTS The cleft skull shows a well-developed set of paranasal sinuses. There are close, significant relationships between MSV and the cranial measurements. The cleft skull had a MSV that does not deviate substantially from that predicted from the size of its facial skeleton. CONCLUSION This study indicates a close link between the size of the facial skeleton and the MSV in humans, even in case of an untreated bilateral cleft. This, in conjunction with the existing literature, makes it extremely unlikely that the sizes of the paranasal sinuses are a factor for sinusitis in patients with cleft lip, alveolus and palate.