Controlled central advancement of the midface after Le Fort III osteotomy by a 3-point skeletal anchorage.

A 3-point skeletal anchorage with taping screws for distraction osteogenesis after a Le Fort III osteotomy was applied for the first time in a severely mentally impaired patient where intraoral devices had to be avoided. All 3-force application points included the center of resistance, which allowed an optimal control on the resulting moment. A novel device for skeletal long-term retention into the nasal dorsum prevented a relapse, whereas adjustment of the midface position was observed. Fusioned three-dimensional computed tomography analysis revealed real movements not accessible by a conventional cephalometry.

Single-stage sinus augmentation with cancellous iliac bone and anorganic bovine bone in the presence of platelet-rich plasma in the miniature pig.

AIM: The aim of the present study was to evaluate the osseointegration of dental implants and bone formation in maxillary sinus grafting with autologous and anorganic bovine bone in the presence of platelet-rich plasma (PRP) in an established animal model. MATERIAL AND METHODS: We performed bilateral maxillary sinus augmentation with 50% anorganic bovine bone and simultaneously inserted a titanium screw implant in five minature pigs. Six hundred microlitre autologous PRP were added to the left side (test). The right side (no PRP) served as control. Polychrome sequential labeling was performed. The animals were sacrificed 6 weeks after surgery. Undecalcified ground sections were evaluated by microradiography, digitized histomorphometry and under fluorescent light. RESULTS: The mean bone implant content in the test and control group was 8.4% and 17.3% respectively (P=0.042). The mean height of newly formed mineralized bone in the augmented area of the test group was 3.6 mm and 5.7 mm respectively (P=0.342). In the PRP group, the mean area of newly formed bone in the base of the sinus was enhanced (75.23%) as compared to the control side (51.8%) (P=0.020(*)). Although PRP enhanced bone formation at the base of the maxillary sinus, it neither improved osseointegration of dental implants nor bone in-growth into the bone substitute under the selected experimental conditions.

HDR brachytherapy irradiation of the jaw - as a new experimental model of radiogenic bone damage.

INTRODUCTION: Hitherto, no suitable experimental model exists to test new treatments for radiogenic bone damage, such as new step from knowledge about bone growth factors or angiogenesis factors. The goal of this investigation was to establish such a standardised experimental model. MATERIAL AND METHODS: Twenty-four rats were used in this study. In 12 rats a plastic tube was implanted along the right half of the mandible and treated with a single dose of 20 Gy at a high-dose-rate (HDR) using an afterloading machine, the remainder served as control (n=12). One hundred days after irradiation both sides of the mandible were examined using paraffin embedding and non-decalcified histology. RESULTS: All HDR irradiated rats developed localised alopecia within 2 weeks of radiotherapy. In the irradiated group, a clear growth reduction of the ipsilateral incisor was observed. Paraffin histology revealed minimal damage of the bone structure with slightly increased signs of regeneration. The bone apposition rate was significantly reduced on the irradiated right side, compared with the left side (p=0.028). The average diameter of the mandibular condyles on the irradiated right sides was significantly reduced when compared with the left sides (p=0.023). CONCLUSIONS: It is possible to induce radiogenic damage of the mandible by using HDR brachytherapy with a single dose of 20 Gy comparable to 45 x 2 Gy of conventional irradiation. This new model is easy and predictable and appears to be suitable for the testing of new treatment modalities. It is advantageous for the testing of bone growth and angiogenesis factors that the contralateral side exhibits completely normal bone apposition characteristics enabling a split-mouth design for future experiments.

BMP-2 and bFGF in an irradiated bone model.

INTRODUCTION: Basic fibroblast growth factor (bFGF) is considered to enhance angiogenesis and to support bone formation in the presence of vital bone cells. Bone morphogenetic protein-2 (rhBMP-2) is known to induce bone formation. The aim of this study was to analyze the effect of bFGF and rhBMP-2 in the irradiated mandible. MATERIAL AND METHODS: The right mandibles of 24 rats were irradiated with a single dose of 20 Gy at a high-dose-rate (HDR) after loading machine (bio effective equivalent dose to ca. 45 x 2 Gy). After 12 weeks 100 microg rhBMP-2 (n=6 animals, group 1), 100 microg bFGF (n=6 animals, group 2) and 100 microg rhBMP-2 plus 100 microg bFGF (n=6 animals, group 3) were injected along the right mandible (left mandible: no irradiation, no growth factor). Another 6 animals (group 4) remained untreated after the irradiation. After another 7 weeks the specimens were examined by non-decalcified histology. RESULTS: Bone apposition of the experimental versus control sides was not statistically significantly different when one of the growth factors was applied alone (rhBMP-2: p=0.917; bFGF: p=0.345). Average bone apposition was significantly decreased on the experimental sides of group 3 (rhBMP-2+bFGF: p=0.046) and group 4 (p=0.008). Average bone densities were unaffected in all settings (for all p>0.1). CONCLUSIONS: The application of bFGF and the application of rhBMP-2 alone did result in predictable bone generation in the irradiated mandible with the bone apposition being equal to that of the non-irradiated side. The application of both growth factors together or none at all after irradiation results in significantly reduced bone apposition.

Interactive effects of periodontitis and orthodontic tooth movement on dental root resorption, tooth movement velocity and alveolar bone loss in a rat model.

BACKGROUND: Many adult orthodontic patients suffer from chronic periodontitis with recurrent episodes of active periodontal inflammation. As their number is steadily increasing, orthodontists are more and more frequently challenged by respective treatment considerations. However, little is currently known regarding interactive effects on undesired dental root resorption (DRR), tooth movement velocity, periodontal bone loss and the underlying cellular and tissue reactions. MATERIAL AND METHODS: A total of 63 male Fischer344 rats were used in three consecutive experiments employing 21 animals each (A/B/C), randomly assigned to 3 experimental groups (n=7, 1/2/3), respectively: (A) CBCT; (B) histology/serology; (C) RT-qPCR-(1) control; (2) orthodontic tooth movement (OTM) of the first/second upper left molars (NiTi coil spring, 0.25N); (3) OTM with experimentally induced periodontitis (cervical silk ligature). After 14days of OTM, we quantified blood leukocyte level, DRR, osteoclast activity and relative gene expression of inflammatory and osteoclast marker genes within the dental-periodontal tissue as well as tooth movement velocity and periodontal bone loss after 14 and 28 days. RESULTS: The experimentally induced periodontal bone loss was significantly increased by concurrent orthodontic force application. Periodontal inflammation during OTM on the other hand significantly augmented the extent of DRR, relative expression of inflammatory/osteoclast marker genes, blood leukocyte level and periodontal osteoclast activity. In addition, contrary to previous studies, we observed a significant increase in tooth movement velocity. CONCLUSIONS: Although accelerated tooth movement would be favourable for orthodontic treatment, our results suggest that orthodontic interventions should only be performed after successful systematic periodontal therapy and paused in case of recurrent active inflammation.

Reference genes for valid gene expression studies on rat dental, periodontal and alveolar bone tissue by means of RT-qPCR with a focus on orthodontic tooth movement and periodontitis.

OBJECTIVES: To obtain valid results in relative gene/mRNA-expression analyses by RT-qPCR, a careful selection of stable reference genes is required for normalization. Currently there is little information on reference gene stability in dental, periodontal and alveolar bone tissues of the rat, especially regarding orthodontic tooth movement and periodontitis. We therefore aimed to identify the best selection and number of reference genes under these experimental as well as physiological conditions. MATERIALS AND METHODS: In 7 male Fischer344-rats the upper left first and second molars were moved orthodontically for 2 weeks and in 7 more animals additionally subjected to an experimental periodontitis, whereas 7 animals were left untreated. Tissue samples of defined size containing both molars (without crowns) as well as the adjacent periodontal and alveolar bone tissue were retrieved and RNA extracted for RT-qPCR analyses. Nine candidate reference genes were evaluated and ranked according to their expression stability by 4 different algorithms (geNorm, NormFinder, BestKeeper, comparative ΔCq). RESULTS: PPIB/YWHAZ were the most stabile reference genes for the combined dental, periodontal and alveolar bone tissue of the rat overall, in untreated animals and rats with additional periodontitis, whereas PPIB/B2M performed best in orthodontically treated rats with YWHAZ ranking third. Gene-stability ranking differed considerably between investigated groups. A combination of two reference genes was found to be sufficient for normalization in all cases. CONCLUSIONS: The substantial differences in expression stability emphasize the need for valid reference genes, when aiming for meaningful results in relative gene expression analyses. Our results should enable researchers to optimize gene expression analysis in future studies by choosing the most suitable reference genes for normalization.

Changes in nose symmetry in unilateral cleft lip and palate treated by differing pre-surgical assistance: An objective assessment of primary repair.

BACKGROUND: Residual deformity of the nose, not lip, continues to be the greater challenge in UCCLP rehabilitation. Platform distortions often re-emerge following primary reconstruction revealing the stereotypical cleft-nose. Nasal alveolar molding reduces nose asymmetry. However, this study applies directional mechanics to the underlying platform distortions and soft tissue nose, introducing a novel device addressing the distorted septo-premaxillary junction. METHODS: Retrospective assessment of 47 UCCLP patients by 2-dimensional photographic analysis with 24 subjects treated by dento-maxillary advancement (DMA) and nasal septum button-head pin (NSBP), 17 having nasal molding (NM), compared to 23 subjects without nose treatment, 16 with DMA and 7 with passive plates. Measurements were assessed by t tests, ≤ 05 confidence. RESULTS: Frontal view: nose-treatment sample achieved ideal ala-bases vertical symmetry (p = 0.00065 & 0.00073); significantly improved ala-rims "slump" angle (p = 0.0071). Both samples had nose positioning within the facial frame like non-cleft population. Sub-nasal view: significant differences were for columella angle (p = 0.0015), nares "offset" (p = 0.002), and columella symmetry (p = 0.022) with nose-treatment achieving near ideal columella symmetry score (0.92) vs. (0.81). CONCLUSIONS: NM and the novel NSBP procedures integrated with the platform correction effect of the DMA successfully treated at three distorted anatomic-levels native to UCCLP to improve nasal aesthetics.

Bone formation in the presence of platelet-rich plasma vs. bone morphogenetic protein-7.

Growth factors contained in platelet-rich plasma (PRP) have recently been proposed to enhance maturation of bone grafts and, in combination with anorganic bovine bone, to support repair in the treatment of small bone defects in maxillofacial surgery. Bone morphogenetic proteins (BMP) carried in a matrix may be able to replace the autologous bone graft in the treatment of critical size defects. However, no studies have compared the bone stimulating capacity of PRP and BMP. Likewise there is no data comparing the effects of PRP in either an autologous bone graft or in anorganic bovine bone. We augmented the mandible of Wistar rats (n = 28) on both sides with either anorganic bovine bone (Bio-Oss) or autologous rib bone. On the test side we applied either 20 microl of autologous PRP or 10 microl of rhBMP-7 (4 groups, n = 7). In addition, bone induction was evaluated in an extraskeletal site (n = 14). A polychrome sequential labeling was performed. The animals were sacrificed by intra-vital perfusion on day 50. Undecalcified ground sections were evaluated by microradiography, digitized histomorphometry and under fluorescent light. The qualitative analysis of fluorochrome labels suggested that PRP and rhBMP-7 accelerated bone growth. However, histomorphometric analysis revealed no significant differences in the area of newly mineralized bone under either the influence of PRP or rhBMP-7 on autologous bone graft. Likewise, the addition of PRP to anorganic bovine bone showed no statistical difference to the control group. The strongest bone stimulating effect was seen for the combination of rhBMP-7 with anorganic bovine bone (p = 0.028). In the extraskeletal model, newly formed bone was evident in the presence of rhBMP-7, but not of PRP. In conclusion, according to the histomorphometry, the addition of platelet-rich plasma failed to enhance bone formation on anorganic bovine bone and on autologous bone grafts.

Reconstruction of the lower lip: rationale to preserve the aesthetic units of the face.

BACKGROUND: The boundaries of the aesthetic units of the face are often crossed after lower lip cancer surgery. The aim of this study was to compare the aesthetic and functional outcome after use of different operative techniques based on the concept of the aesthetic units of the face. MATERIALS: Sixty-three patients were evaluated after lower lip reconstruction. The aesthetic outcome was recorded by standard photography evaluating the disruption of the boundaries of the aesthetic units of the face, lip projection, and the resulting facial expression. The functional outcome consisted of the evaluation of mouth opening, pouting, and lips at rest for the evaluation of mouth continence. Three techniques were used: wedge excision, the Webster-Fries method, and the step technique. The step technique was combined with an Abbé or an Estlander flap in defects involving more than two-thirds of the lip. RESULTS: In defects involving up to one-third of the lip, the aesthetic outcome was better for the step technique than for wedge excision (a statistical trend was observed, p = 0.088). In defects involving two-thirds of the lip, the aesthetic and functional outcome was better using the step technique than the Webster-Fries method (p = 0.002), because the boundaries of the aesthetic units are respected. In defects involving more than two-thirds of the lip, the result was better using the step technique combined with the Abbé flap. CONCLUSION: The authors have shown that the step technique alone or combined with a flap of the opposite lip is a rational approach for preserving the aesthetic units of the face and its function.

Sinus floor augmentation with simultaneous placement of dental implants in the presence of platelet-rich plasma or recombinant human bone morphogenetic protein-7.

The aim of the present study was to evaluate the possible benefit of platelet-rich plasma (PRP) in sinus grafting as compared with recombinant human bone morphogenetic protein-7 (rhBMP-7). For this purpose, we performed a bilateral sinus augmentation with anorganic bovine bone and simultaneous insertion of a titanium screw implant in five miniature pigs. Six hundred microliters of PRP and 15%-vol. autologous bone, which was collected with a trap during preparation of the implant recipient site, were added to the right sinus and 420 microl rhBMP-7 to the left sinus. A polychrome sequential labeling was performed. The animals were sacrificed 6 weeks after surgery. Undecalcified ground sections were evaluated by microradiography, digitized histomorphometry and under fluorescent light. The mean bone-implant contact using rhBMP-7 was 45.8% and 5.7% under PRP (P=0.002). The mean height of newly mineralized bone in the augmented area using rhBMP-7 amounted to 8.3 mm as opposed to 3.6 mm under PRP (P=0.013). Using PRP, the mean area of the newly formed bone was enhanced (51.3%) as compared with rhBMP-7 (33.1%); however, this difference was not statistically significant (P=0.081). In conclusion, under the selected experimental conditions the use of rhBMP-7 led to superior outcomes with regard to the osseointegration of dental implants and the height of new bone as compared with the use of PRP.