Mandibular Distraction Osteogenesis in Children and Adolescents: A Clinical and Radiographic Research Using Cone-Beam Computed Tomography.

AIM: The aim of this cross-sectional study was to evaluate, via cone-beam computed tomography, the long-term postoperative outcome in children treated with mandibular distraction osteogenesis. MATERIALS AND METHODS: All young patients treated with mandibular distraction osteogenesis (MDO), during a 16-year period, at the University Department of Oral and Maxillofacial Surgery of a Pediatric Hospital, were recalled, and various clinical and radiographic parameters were recorded. RESULTS: Eleven patients were included: 5 with hemifacial microsomia (HFM) and 6 with mandibular micrognathia. In all cases, MDO had been successful in regular follow-up and decannulation, soon after MDO, was achieved in all tracheostomy cases. The long-term result in cases of HFM was found stable, functionally and esthetically accepted, although less satisfactory than in regular follow-up; in micrognathia patients, relapse of different degrees was registered in 4 of 6 cases, without any need for tracheostomy though. Detailed and accurate information was obtained by cone-beam computed tomography (CBCT). The shape of the regenerated bone was irregular in HFM cases and relatively normal in the micrognathia cases. Quality of the regenerated bone was normal in all patients. The irregular shape registered in HFM cases did not compromise a safe orthognathic operation. CONCLUSIONS: Distraction osteogenesis remains an early treatment choice in cases of mandibular deformities. Long-term findings showed that there is a degree of relapse with growth, which was more obvious in mandibular micrognathia cases. Computed tomography contributes to detailed evaluation of changes at the distraction site.

Orthodontic treatment as triggering factor of Medication Related Osteonecrosis of the Jaw in a breast cancer patient. Report of a rare case.

Background: Orthodontic treatment in adult patient is widely accepted nowadays. Therefore, orthodontists are needed to interact with more complex medical histories that may interfere with the orthodontic treatment. Antiresorptive medication is a widely used treatment for osteoporosis or malignancies that may affect the orthodontic movement and planning. Case presentation: A 53-year-old patient diagnosed with MRONJ one year after she started orthodontic treatment. Patients' medical history includes breast cancer and treatment with high doses of denosumab for over 2 years. The patient had a drug holiday period in the start of orthodontic treatment and then resumed antiresorptive medication until extreme tooth mobility was observed during the orthodontic treatment. After a long absence from denosumab and failure of conservative means to control the established MRONJ we proceeded in surgical management of the affected area. After two relapse the patient is now stable and prosthetically rehabilitated. Discussion: The affected area was the only one treated orthodontically and in lack of other triggering factors such as extraction or acute inflammation we consider the orthodontic movement as triggering factor of MRONJ. BPs are widely known to affect orthodontic treatment as they suppress bone remodeling but there is a lack of literature as far as patients treated with denosumab or high doses of antiresorptive medication concern. Conclusions: Patients treated with high doses of antiresorptive medication should considered at high risk of developing MRONJ during orthodontic movement. Although, more studies are needed to establish a protocol for the patients seeking orthodontic treatment and treated with denosumab. Key words:Medication Related Osteonecrosis of the Jaw, MRONJ, orthodontic treatment, bisphosphonates, denosumab, antiresorptive medication, surgical management.

The effect of nano-hydroxyapatite/chitosan scaffolds on rat calvarial defects for bone regeneration.

BACKGROUND: This study aims at determining the biological effect of 75/25 w/w nano-hydroxyapatite/chitosan (nHAp/CS) scaffolds on bone regeneration, in terms of fraction of bone regeneration (FBR), total number of osteocytes (Ost), and osteocyte cell density (CD), as well as its biodegradability. METHODS: Two critical-size defects (CSDs) were bilaterally trephined in the parietal bone of 36 adult Sprague-Dawley rats (18 males and 18 females); the left remained empty (group A), while the right CSD was filled with nHAp/CS scaffold (group B). Two female rats died postoperatively. Twelve, 11, and 11 rats were euthanized at 2, 4, and 8 weeks post-surgery, respectively. Subsequently, 34 specimens were resected containing both CSDs. Histological and histomorphometric analyses were performed to determine the FBR, calculated as [the sum of areas of newly formed bone in lateral and central regions of interest (ROIs)]/area of the original defect, as well as the Ost and the CD (Ost/mm2) in each ROI of both groups (A and B). Moreover, biodegradability of the nHAp/CS scaffolds was estimated via the surface area of the biomaterial (BmA) in the 2nd, 4th, and 8th week post-surgery. RESULTS: The FBR of group B increased significantly from 2nd to 8th week compared to group A (P = 0.009). Both the mean CD and the mean Ost values of group B increased compared to group A (P = 0.004 and P < 0.05 respectively). Moreover, the mean value of BmA decreased from 2nd to 8th week (P = 0.001). CONCLUSIONS: Based on histological and histomorphometric results, we support that 75/25 w/w nHAp/CS scaffolds provide an effective space for new bone formation.

Imaging of nano-hydroxyapatite/chitosan scaffolds using a cone beam computed tomography device on rat calvarial defects with histological verification.

OBJECTIVES: Τhis study aims at determining the ability of cone beam computed tomography (CBCT) to visualize critical-size defects (CSD) created at rat calvaria and filled with 75/25 w/w nano-hydroxyapatite/chitosan (nHAp/CS) scaffolds, prior to their histological investigation. MATERIALS AND METHODS: Thirty adult Sprague Dawley rats, 15 males and 15 females, were used. Two CSD, 5 mm in diameter, were bilaterally trephined in the parietal bone. The right CSD was filled with nHAp/CS scaffold, while the left CSD remained empty, as the control group. Two female rats died post-operatively. Rats were euthanized at 2, 4, and 8 weeks post-surgery. Twenty-eight specimens (15 × 2 × 10 mm) were resected-containing both CSDs-and then scanned using a NewTom VGi CBCT imaging unit (Verona, Italy). The manufacturer's software trace region profile tool (NNT v6.2, Verona, Italy) was used in selected axial slices. The greyscale value (in VGiHU) and the traced/selected region of interest (ROI, in mm2) of those areas were automatically calculated. Subsequently, all specimens were histologically examined. RESULTS: An increased VGiHU (P = 0.000), was observed in the experimental group relative to the control group. The ROI of CSD (in mm2) was significantly reduced (P = 0.001) from the fourth to the eighth week in both groups. No statistically significant difference between male and female rats (P = 0.188) was observed with respect to VGiHU. CONCLUSIONS: The nHAp/CS scaffolds are easily visualized using a particular high-resolution CBCT device. CLINICAL RELEVANCE: Both the CBCT measurements and also the histological results suggest that the nHAp/CS scaffold presence contributes to new bone formation in rat calvarial CSD.

Application of nano-hydroxyapatite/chitosan scaffolds on rat calvarial critical-sized defects: A pilot study

BACKGROUND: The purpose of this pilot study was to evaluate for the first time the effect of 75/25 w/w nano-Hydroxyapatite/Chitosan (nHAp/CS) scaffolds on Guided Bone Regeneration (GBR) in rat calvarial critical-sized defects (CSDs). MATERIAL AND METHODS: Six adult Sprague Dawley rats, 3 males and 3 females, were used. Two CSDs, full thickness and 5mm in diameter, were trephined in both sides of the parietal bone. The right CSD was filled with nHAp/CS scaffold, while the left CSD remained empty, as the control group. The wound was sutured in layers. Rats were euthanized with diethyl ether inhalation at 2, 4 and 8 weeks after surgical procedure. Histological and histomorphometric analysis was performed within distinct regions of interest (ROI): the lateral area inward of the middle sagittal seam; the lateral area outward of the middle sagittal seam and the central area. RESULTS: The mean surface of newly formed bone (in μm2) in the lateral area inward of the middle sagittal seam of all rats was significantly higher (P=0.039) in the experimental group (91733.00±38855.60) than the control group (46762.17±25507.97). The NOex-c, defined as total number of osteocytes (OST) in newly formed bone surface in experimental group [experimental OST] minus the total number of osteocytes in newly formed bone surface in control group [control OST], was significantly greater (P=0.029) at 4th week post-surgery. Within the experimental group, a statistically significant increase (P=0.042) in the surface of newly formed bone was noticed in rats euthanized in 4th week compared with rats euthanized in 2nd week after surgery in the lateral area inward of the middle sagittal seam. CONCLUSIONS: The results of this study suggest that 75/25 w/w nHAp/CS scaffolds should be considered as a suitable biomaterial for GBR

Hand-Schüler-Christian disease presenting with recurrent, bilateral, symmetrical mandibular lesions in an 8-year-old boy: report of a case.

INTRODUCTION: Hand-Schüller-Christian disease (HSC) is the unisystem multifocal form of Langerhans Cell Histiocytosis (LCH) and is primarily seen in infants and children. CASE REPORT: An 8-year-old boy was referred for acute mandibular pain. His medical history included otic LCH and diabetes insipidus at age of 11 months. Intraorally, a pressure sensitive swelling, and radiographically, extensive bone loss were revealed on the area of lower second primary molars. The primary molars were extracted and histological examination confirmed the final diagnosis of HSC. The patient was treated with chemotherapy and the lesions decreased considerably. Two years later, a new swelling was recorded in the same area bilaterally. Biopsy confirmed recurrent HSC disease and the patient entered an alternative chemotherapy protocol. Six months later, improvement of the lesions was revealed. CONCLUSIONS: Dentists can contribute to a timely and valid identification of HSC disease by correctly differentially diagnosing lesions of head and neck.

Management of Intraosseous Vascular Malformations of the Jaws in Children and Adolescents: Report of 6 Cases and Literature Review.

BACKGROUND: Intraosseous vascular malformations represent a rare clinical entity of the facial skeleton. The purpose of the current study was to present our experience in a Greek paediatric population and propose guidelines for the treatment of these jaws anomalies in children and adolescents. METHODS: A retrospective study (from 2009 to 2014) was performed to investigate the features and management of the intraosseous vascular anomalies in a Greek paediatric population. RESULTS: Six patients aged between 6 and 14 years were treated for intraosseous vascular malformations (4 venous and 2 arteriovenous) of the jaws. Five lesions were located in the mandible and one in the maxilla. In four lesions with pronounced vascularity superselective angiography, followed by embolization was performed. Individualized surgical treatment, depending on the size and vascularity of the lesions was applied in 4 patients. CONCLUSIONS: The intraosseous vascular malformations of the jaws may escape diagnosis in paediatric patients. A multidisciplinary approach is important for their safe and efficient treatment. Embolization is recommended for extended high-flow lesions, either preoperatively or as a first-line treatment, when surgery is not feasible without significant morbidity.

Comparative biomechanical evaluation of mono-cortical osteosynthesis systems for condylar fractures using photoelastic stress analysis.

Fractures of the condyle account for 20-30% of all mandibular fractures, and are therefore one of the most common facial injuries. Precise evaluation of the mechanical stresses that develop in a fractured mandible is essential, particularly for the testing of systems currently used for stabilisation of the condylar fragment. Photoelastic stress analysis can be used to visualise alterations in the strain that is induced in the mandible by a fracture, and in the osteosynthesis materials used to stabilise it. This method, used on currently used osteosynthesis materials, showed that stabilisation of a subcondylar fracture with a single miniplate does not provide enough stability, whereas the use of two miniplates - properly positioned - offers sufficient stability in all loading conditions. A microplate may be used as a tension-resisting plate with equally good results.

Prosthodontic treatment of a class IV ACP PDI patient, with Langerhans cell histiocytosis (LCH).

Langerhans cell histiocytosis (LCH) is a disease of unknown etiology with a frustrating and unpredictable course. Surviving adult patients suffering from the multisystem type of the disease present with problems in most organs. This article presents the oral rehabilitation of a 28-year-old patient, with multisystem sequelae that included the oral cavity, classifying him as a Class IV American College of Prosthodontists Prosthodontic Diagnostic Index patient. A 5-year course of treatment is analyzed, starting from merely replacing missing teeth with a removable partial denture. The second stage of prosthetic rehabilitation included replacement of the removable prosthesis with fixed partial dentures. The final and most important aspect of treatment was the 2-year follow-up, when the patient presented with no problems or adverse effects. The purpose of this presentation is to offer an insight to prosthodontic treatment possibilities for patients suffering from multisystem LCH and to show the value of a "team approach" to achieving a positive outcome.

Her-2 immunohistochemical expression in oral squamous cell carcinomas is associated with polysomy of chromosome 17, not Her-2 amplification.

Based on the prognostic role of Her-2 amplification and protein overexpression in breast cancer, various studies have been performed in oral squamous cell carcinomas (OSCC) with inconsistent results. As in invasive breast carcinomas Her-2 overexpression has been related to an increased number of chromosome 17 copies, a common chromosomal alteration in OSCC, we evaluated the association between polysomy 17 and Her-2 protein expression in a series of primary OSCC. Forty-one incisional biopsies of primary OSCC were included in the study. Protein expression was evaluated immunochistochemically with CB11 mouse monoclonal anti-human antibody. The reaction was arbitrarily characterized as absent, faint, moderate, and strong, and staining pattern as cytoplasmic and membranous. Positive cases were analyzed by chromogenic in situ hybridisation (CISH) to access Her-2 status. The association between polysomy 17 and Her-2 expression was checked by Fisher's exact test. Four cases were negative and 37 cases were positive for Her-2. Staining was faint in 15 cases and moderate in 22 cases. CISH showed that all cases with faint staining were diploid, while from the cases with moderate staining 10 were diploid and 12 polysomic for chromosome 17. Thirteen cases showed purely cytoplasmic staining, while in 24 there were areas of both cytoplasmic and membranous staining. There was a statistically significant correlation between intensity of the reaction and polysomy 17 (P = 0.0036), in particular for cases with both cytoplasmic and membranous staining (P = 0.0128). In some OSCC Her-2 immunohistochemical expression may be associated with chromosome 17 polysomy and not Her-2 amplification.