Maxillary canine position of patients with non-syndromic craniofacial disorder: a retrospective evaluation of panoramic radiographs.

BACKGROUND: The study evaluates the position and displacement tendency of unerupted maxillary canines in orthodontic patients with non-syndromic craniofacial disorders (CD) compared to a control (C) group. METHODS: Canine position and displacement tendency were evaluated using panoramic radiographs (PAN) examined with parameters such as sector classification (sectors 1-5) and inclination angles (α and ß). The displacement tendency was defined as the positioning of the tip in sectors 1 or 2, as well as its combination with increased angles (α > 30° and ß > 39°). In addition, the correlation of the tooth position and agenesis, cleft side, and sex was assessed. RESULTS: A total of 116 pre-treatment PAN, divided into the CD group (n = 50; mean age 8.32 ± 2.27 years) and the C group (n = 66; mean age 10.80 ± 2.82 years), were evaluated in this study. The sector classification showed no displacement tendency in both groups. Inclination angles α/ß showed a statistically significant higher displacement tendency (p = 0.01) of the CD group (n = 5) on the right side, compared to healthy subjects (n = 1). Male CD patients had a statistically significant higher displacement tendency on the right side (p = 0.03). A statistically significant correlation between cleft and non-cleft-side (p = 0.03) was found. CONCLUSION: Patients with CD showed a statistically significant higher displacement tendency of the maxillary canine affected by the cleft side. The inclination angle was found to be the better predictor compared to the sector classification which should be considered in the orthodontic treatment planning.

Retrospective evaluation of the orthodontic treatment needs in primary school children with Robin sequence following Tübingen palatal plate therapy in infancy.

INTRODUCTION: The aim of this study was to investigate the orthodontic treatment needs (OTN) of children with RS treated with the TPP in infancy compared to age- and sex-matched controls. METHODS: The aim of this study was to investigate the orthodontic treatment needs (OTN) of children with RS treated with the TPP in infancy compared to age- and sex-matched controls. RESULTS: In 21 children with RS (n = 23; 19 non-syndromic, 4 syndromic; average age 9.9 years) showed high OTN, which was significantly higher than in controls (n = 21). The latter of 9 controls had minor OTN, followed by 8 participants with borderline OTN. Regarding the intraoral picture, patients with RS had an increased open bite tendency. Without considering the presence of a cleft palate, 16 children with RS had high or very high OTN, compared to 4 of controls. CONCLUSIONS: Patients with RS have significantly higher OTN than healthy controls, independent of cleft occurrence. RS is associated with dental anomalies and special skeletal growth patterns, both increasing malocclusion and negatively affecting dentoalveolar growth. This should raise awareness for identifying these needs and provide a comprehensive orthodontic treatment, where functional rehabilitation should be favored over aesthetic results.

Tooth agenesis in German orthodontic patients with non-syndromic craniofacial disorder: a retrospective evaluation of panoramic radiographs.

OBJECTIVES: The study objective was to evaluate the tooth agenesis in German orthodontic patients with non-syndromic cleft lip and/or palate and Robin sequence compared to a control group without craniofacial disorder. MATERIALS/METHODS: A total of 108 panoramic radiographs were examined using the binary system of Tooth Agenesis Code (TAC) (excluding the third molar). Patients were divided into the craniofacial disorder group 1 (n = 43) and the healthy control group 2 (n = 65). Parameters such as skeletal class malformation, sex, localization of the cleft, craniofacial disorder, and interobserver reliability were assessed. RESULTS: Permanent tooth agenesis was observed in 44% of group 1 and 14% in group 2 with a statistically significant higher prevalence (p = 0.00162 (χ2)). Fourteen different TAC patterns were observed in group 1, ten of these occurring only once in separate patients. The distribution of the TAC codes in group 2 showed nine different possibilities of TAC code patterns; seven TACs were unique. In group 1, the most frequently absent teeth were the maxillary lateral incisor of the left side (30%); in group 2, the second premolar of the lower jaw on the right side (9%). Male patients with craniofacial disorder showed a higher percentage of tooth agenesis than female. CONCLUSION: The data presented here shows a statistically significant higher prevalence of tooth agenesis in German patients with non-syndromic craniofacial disorder. CLINICAL RELEVANCE: Radiographic evaluation enables the diagnosis of tooth agenesis. Recognizing early on the higher prevalence of tooth agenesis in patients exhibiting a craniofacial disorder is an important issue when developing long-term and comprehensive interdisciplinary treatment.

Influence of Extracellular Acidosis on Matrix Protein Homeostasis in Tumour Cells and Fibroblasts.

Pathogenesis of tumour development comprises among others changes of its microenvironment that can be caused by tumour cells or stroma cells like fibroblasts and include extracellular acidosis. Acidosis then may have impact on tumour cells, fibroblasts and their cross-talk, leading for example to an altered matrix protein homeostasis. The mentioned changes can support tumour progression. In the present study the influence of metabolic acidosis on matrix proteins in tumour cells, fibroblasts and their co-culture was evaluated. The experiments were performed in rat tumour cells (AT-1), normal rat kidney fibroblasts (NRKF) and their co-culture. Cells were exposed to acidic media for up to 48 h. Changes of collagen I and fibronectin were measured: mRNA content by RT-PCR, intracellular protein by immune blot and extracellular proteins by direct ELISA. In AT-1 cells acidosis led to decreased secretion of collagen I and fibronectin. The mRNA of both was unchanged and intracellular collagen I was decreased. In NRKF extracellular collagen I was increased and fibronectin unchanged. The collagen I and fibronectin mRNA was unchanged and intracellular collagen I was increased. In the co-culture media, collagen I changes vanished and fibronectin was decreased. In co-culture the mRNA content of collagen I and fibronectin in AT-1 was unchanged but both were increased in NRKF. In AT-1 and NRKF mono-culture extracellular matrix protein changes seem to be the result of posttranscriptional regulation.

Autogenous bone and a bovine bone substitute for ridge preservation: preliminary clinical and histologic findings.

BACKGROUND: Tooth extractions lead to morphological changes of the alveolar ridge. For oral rehabilitation sufficient bone volume of the alveolar ridge is required. This clinical study compared the ability of Bio-Oss® Collagen to autogenous bone to preserve bone volume after tooth extraction. METHODS: A total of 17 patients with 20 extraction sites were examined. After extraction, 10 sockets were each filled with either autogenous bone or Bio-Oss® Collagen and covered with a resorbable membrane. The width of the alveolar ridge was measured postoperatively, and after 4 and 6 months respectively. Prior to implant insertion, a bone biopsy was taken from the grafted sites and evaluated histologically. RESULTS: The width of the alveolar ridge in the Bio-Oss® Collagen group decreased about 5.33 ± 6.62% after 4 months and 9.45 ± 10.51% after 6 months. The reduction in the group augmented with autogenous bone was 14.31 ± 21.41% after 4 months and 19.17 ± 8.38% after 6 months. No statistically significant differences were observed. The histological examination showed comparable area fractions of total bone in both groups (Bio-Oss® Collagen: 59.99 ± 24.23%; autogenous bone: 61.55 ± 25.13%; p = 1.0). CONCLUSIONS: The present study demonstrated that autogenous bone and Bio-Oss® Collagen are suitable for ridge preservation. However, both techniques could not entirely prevent tissue volume loss.

MRI and dental implantology: two which do not exclude each other.

Currently, histological techniques are used to analyse implant-tissue-interactions. However, these methods are destructive and time-consuming. Furthermore, they require a large number of animals as longitudinal observations in one individual are not possible. The evaluation by non-destructive imaging techniques provides the opportunity to study the osseous integration with a reduced number of animals and a decreased biological variability. The present study examined the suitability of magnetic resonance imaging (MRI) to assess peri-implant bone formation exemplarily for a dental implant in a minipig model. Due to its compatibility to MR imaging polyetheretherketone (PEEK) coated with a thin layer of titanium was applied as implant material. Osseointegration was analysed within different peri-implant regions quantifying bone volume density and soft tissue content, which were assessed by MRI and histology, likewise. It could be proven that the examined regions showed differences in bone formation; the region adjacent to the implant apex turned out to be the most dynamic. Both methods led to comparable results with no significant differences regarding to the assessed parameters. Moreover, it was demonstrated that titanium coated PEEK showed a sufficient osseointegration and MRI provides a promising application in monitoring bone formation.

Efficacy of tissue engineered bone grafts containing mesenchymal stromal cells for cleft alveolar osteoplasty in a rat model.

UNLABELLED: The development of sufficient tissue engineered bone grafts for alveolar cleft osteoplasty could reduce the necessity of autogenous bone grafts and its donor site morbidity. The aim of the study was to evaluate tissue engineered bone grafts in an artificially created bone defect. Bone grafts were created in vitro colonizing a synthetic hydroxyapatite-tricalciumphosphate scaffold (BONITmatrix(®)) with either undifferentiated mesenchymal stromal cells (group 1) or osteogenic differentiated mesenchymal stromal cells (group 2). Cells were multiplied from bone marrow of donor rats. Unmodified scaffolds (group 3) and the tissue engineered bone grafts were inserted into artificial maxillary defects of 54 Lewis rats. In 18 animals the defects remained unfilled (control). After one, three and six weeks the rats were sacrificed. The defect was evaluated radiologically and histologically with regard to the remaining defect volume and diameter. Statistical analysis followed. The bone grafts led to a specific bone formation at the defect margin. No complete reunion of any defect was observed within the healing time. After six weeks, the remaining defect volume was 6.86 ± 3.21 mm(3) (control), 4.08 ± 1.36 mm(3) (group 1), 5.00 ± 0.84 mm(3) (group 2) 5.50 ± 1.05 mm(3) (group 3). The remaining defect diameter measured 2.63 ± 0.52 mm (control), 2.39 ± 0.23 mm (group 1), 2.53 ± 0.22 mm (group 2) and 2.70 ± 0.66 mm (group 3). In all experimental groups the defect volume and diameter decreased over time, which was significant for group 1 (p = 0.014), group 2 (p = 0.025) and group 3 (p = 0.048). The defect volume and width was significantly reduced for bone grafts containing undifferentiated cells compared to control (p = 0.035) or scaffolds only (p = 0.05). CONCLUSION: Tissue engineered bone grafts induce a pronounced bone formation in artificial bone defects compared to unfilled controls or scaffolds only.

Experimental findings on customized mandibular implants in Göttingen minipigs - a pilot study.

Reconstructing continuity defects of the mandible is still challenging for surgeons. The currently applied conventional titanium bridging plates have considerable rates of complications. Now, a new technology enables an individual shape-identical creation of a mandibular implant in a form-board design by the method of LaserCUSING using pure titanium. This technology has been successfully performed in previous examinations to individually reconstruct mandibular continuity defects. This pilot study evaluated the surgical procedure in 10 female Göttingen mini pigs. First, a computed tomography scan from a mini pig cranium was performed. A three-dimensional model of the mandible was designed by data conversion. Based on the data, a customized mandibular implant resembling the natural shape was virtually created and manufactured. Then, a continuity defect of the left mandible was created in a standardized way. The implants were inserted into the defect and the wounds were allowed to heal for 21, 35, 56 and 180 days. During the healing period, no signs of inflammation or infection were observed. After the sacrifice of the minipigs the mandibles were resected. Histological microsections using Donath's sawing and grinding technique were manufactured and stained with Masson Goldner trichrome staining. The histomorphological results showed a pronounced ossification at the outer and inner surface of the implants. This animal study describes a promising approach to optimize customized implants for the application in humans.

Chondroitin sulfate and sulfated hyaluronan-containing collagen coatings of titanium implants influence peri-implant bone formation in a minipig model.

An improved osseous integration of dental implants in patients with lower bone quality is of particular interest. The aim of this study was to evaluate the effect of artificial extracellular matrix implant coatings on early bone formation. The coatings contained collagen (coll) in conjunction with either chondroitin sulfate (CS) or sulfated hyaluronan (sHya). Thirty-six screw-type, grit-blasted, and acid-etched titanium implants were inserted in the mandible of 6 minipigs. Three surface states were tested: (1) uncoated control (2) coll/CS (3) coll/sHya. After healing periods of 4 and 8 weeks, bone implant contact (BIC), bone volume density (BVD) as well as osteoid related parameters were measured. After 4 weeks, control implants showed a BIC of 44% which was comparable to coll/CS coated implants (48%) and significantly higher compared to coll/sHya coatings (37%, p = 0.012). This difference leveled out after 8 weeks. No significant differences could be detected for BVD values after 4 weeks and all surfaces showed reduced BVD values after 8 weeks. However, at that time, BVD around both, coll/CS (30%, p = 0.029), and coll/sHya (32%, p = 0.015), coatings was significantly higher compared to controls (22%). The osteoid implant contact (OIC) showed no significant differences after 4 weeks. After 8 weeks OIC for controls was comparable to coll/CS, the latter being significantly higher compared to coll/sHya (0.9% vs. 0.4%, p = 0.012). There were no significant differences in osteoid volume density. In summary, implant surface coatings by the chosen organic components of the extracellular matrix showed a certain potential to influence osseointegration in vivo.

Treatment of cooling tower blowdown water containing silica, calcium and magnesium by electrocoagulation.

This research investigated the effectiveness of electrocoagulation using iron and aluminium electrodes for treating cooling tower blowdown (CTB) waters containing dissolved silica (Si(OH)(4)), Ca(2 + ) and Mg(2 + ). The removal of each target species was measured as a function of the coagulant dose in simulated CTB waters with initial pH values of 5, 7, and 9. Experiments were also performed to investigate the effect of antiscaling compounds and coagulation aids on hardness ion removal. Both iron and aluminum electrodes were effective at removing dissolved silica. For coagulant doses < or =3 mM, silica removal was a linear function of the coagulant dose, with 0.4 to 0.5 moles of silica removed per mole of iron or aluminium. Iron electrodes were only 30% as effective at removing Ca(2 + ) and Mg(2 + ) as compared to silica. There was no measurable removal of hardness ions by aluminium electrodes in the absence of organic additives. Phosphonate based antiscaling compounds were uniformly effective at increasing the removal of Ca(2 + ) and Mg(2 + ) by both iron and aluminium electrodes. Cationic and amphoteric polymers used as coagulation aids were also effective at increasing hardness ion removal.