Exogenously added BMP-6, BMP-7 and VEGF may not enhance the osteogenic differentiation of human adipose stem cells.

In the present study bone morphogenetic protein (BMP)-6 alone or in synergy with BMP-7 and vascular endothelial growth factor (VEGF) were tested with human adipose stem cells (hASCs) seeded on cell culture plastic or 3D bioactive glass. Osteogenic medium (OM) was used as a positive control for osteogenic differentiation. The same growth factor groups were also tested combined with OM. None of the growth factor treatments could enhance the osteogenic differentiation of hASCs in 3D- or 2D-culture compared to control or OM. In 3D-culture OM promoted significantly total collagen production, whereas in 2D-culture OM induced high total ALP activity and mineralization compared to control and growth factors groups, but also high cell proliferation. In this study, hASCs did not respond to exogenously added growth although various parameters of the study set-up may have affected these findings contradictory to the previous literature.

Beta-tricalcium phosphate/type I collagen cones with or without a barrier membrane in human extraction socket healing: clinical, histologic, histomorphometric, and immunohistochemical evaluation.

The aim of this study was to investigate the healing of human extraction sockets filled with ß-tricalcium phosphate and type I collagen (ß-TCP/Clg) cones with or without a barrier membrane. Twenty patients were divided in two groups: (A) ß-TCP/Clg non-membrane and (B) ß-TCP/Clg + barrier membrane. Clinical examination and biopsies from the grafted sites were collected 9 months later. Bone samples were analyzed using histomorphometry and immunohistochemistry. The horizontal dimension of the alveolar ridge was significantly reduced 9 months after socket preservation in the non-membrane group. There was bone formation with no significant differences between the two groups in the areas occupied by new bone (A = 42.4%; B = 45.3%), marrow (A = 42.7%; B = 35.7%), or residual graft (A = 9.7%; B = 12.5%). Immunohistochemistry revealed osteonectin expression in both groups. Both groups demonstrated sufficient amounts of vital bone and socket morphology to support dental implant placement after the 9-month healing period. A future trial to evaluate the alveolar outcomes at an earlier 6-month time point rather than the 9 months used in this study would be of interest.

Posterior cranial vault distraction osteogenesis in craniosynostosis: estimated increases in intracranial volume.

PURPOSE: To study distraction osteogenesis of the posterior cranial vault in children requiring increased intracranial volume. MATERIALS AND METHODS: Ten patients were treated with cranial distractors. Five children had previously been operated for scaphocephaly and one child for Saether-Chotzen syndrome. Two patients had bilateral coronal suture synostosis with Muenke syndrome and two patients had Apert syndrome. At surgery, the cranial bones were mobilized, the head was widened during surgery, and the segments fixed to each other with distractors. Further expansion at a rate of 1 mm/day was performed over 2-4 weeks. The cranium was distracted posteriorly from 20 to 30 mm. RESULTS: The patients all tolerated surgery and distraction well. In all cases, the parents were able to perform the distraction at home. There were no technical problems with the distraction devices. Two cases had minor cutaneous problems, where the distractor penetrated the skin. These cases responded to gentle local wound care measures. At the time of distractor removal, ossification had occurred sufficiently in one of these two cases. In the other case, the device was removed and replaced with a resorbable plate, without any harmful effect on the result. In all cases, sufficient expansion was achieved without causing more cosmetic deformity. Ossification occurred in all cases. This method seems effective, as the calculated increase in intracranial volume was a mean of 20.2% (range 10.2-28.5%). CONCLUSIONS: This preliminary series shows that cranial bone distraction is a useful method for cranial expansion with low morbidity in children with craniosynostosis.

Addition of BMP-2 or BMP-6 to dexamethasone, ascorbic acid, and ß-glycerophosphate may not enhance osteogenic differentiation of human periodontal ligament cells.

This study was designed to investigate the potential merits of the combined use of bone morphogenetic protein (BMP)-2 or BMP-6 and osteogenic supplements (OS) [dexamethasone, ascorbic acid (AA), and ß-glycerophosphate] on osteogenic differentiation of periodontal ligament cells (PDLCs). Osteogenic differentiation was evaluated by quantitative alkaline phosphatase (ALP) assay, alizarin red staining, quantitative calcium assay, and the qRT-PCR analysis for the expression of collagen type I, runt-related transcription factor-2, osteopontin (OPN), and osteocalcin in PDLCs. Culture with BMP-2 or BMP-6+AA increased ALP activity of PDLCs, suggesting their osteo-inductive effects. However, longer duration of culture showed neither of the BMPs induced in vitro mineralization. In contrast, OS were able to increase ALP activity and OPN expressions, and also induced in vitro mineralization. The mineralization ability was not enhanced by the addition of BMP-2 or BMP-6. These findings suggest that the addition of BMP-2 or BMP-6 to OS may not enhance an osteogenic differentiation of hPDLCs.

Finite element analysis of the human mandible to assess the effect of removing an impacted third molar.

BACKGROUND AND AIM: Finite element analysis (FEA) was used to generate 3-dimensional models of a human mandible with impacted third molars. The aim was to analyze the effects of removing various amounts of bone around an impacted mandibular third molar and to predict the possibility of iatrogenic fracture. MATERIALS AND METHODS: Data were acquired from cone beam computed tomography (CBCT) scans of a patient using numerically calculated mechanical parameters. Virtual surgery was then performed on the mandibular models, and standardized chewing forces were applied to the resulting simulations. RESULTS: The modelling showed that the highest stress during normal clenching occurred if the surgical procedure involved the external oblique ridge. The peak stress occurred at the site of removal of the third molar, during contralateral loading of the mandible. DISCUSSION: Use of CBCT allowed production of high-quality models of an individual patient and simulation of various surgical scenarios. FEA identified the accumulation of stress and strain at specific parts of the mandible and predicted the responses of bone to mechanical activity. FEA could prove useful to dental practitioners in the future to predict the likelihood of iatrogenic fracture of the jaws after surgical removal of mandibular bone, such as occurs when the third molar is removed. This may allow dentists to change their approach to tooth removal in certain cases.

Lemierre syndrome from an odontogenic source: a review for dentists.

Lemierre syndrome, which can result from a recent oropharyngeal or odontogenic infection, is characterized by clinical or radiographic signs of thrombosis of the internal jugular vein, distant infected emboli and the presence of anaerobic pathogens, usually Fusobacterium necrophorum. The septic emboli resulting from the infected thrombophlebitis of the internal jugular vein give the syndrome its constellation of central nervous system, pulmonary and many other manifestations including septic shock. This condition was so rare that, historically, it became known as the "forgotten disease," but an increasing frequency of reports indicates that Lemierre syndrome may not be so uncommon.

Augmentation of the maxillary sinus: comparison of bioimplants containing bone morphogenetic protein and autogenous bone in a rabbit model.

OBJECTIVE: To evaluate the effectiveness of various bioimplants used for augmentation of the maxillary sinus floor by means of a rabbit model. MATERIALS AND METHODS: Bone was harvested from the posterior iliac crest of 40 adult New Zealand white rabbits to allow bilateral augmentation of the floor of the maxillary sinus with autogenous bone or other materials. One of the following was grafted to the maxillary sinus of each rabbit: particulated autogenous bone, demineralized bone matrix (DBM), DBM combined with purified bone morphogenetic protein (BMP-DBM bioimplants) and bioimplants consisting of a poloxamer gel with BMP in 1 of 2 different doses. Animals were sacrificed at 2 or 8 weeks. Histologic examination was used to assess biologic healing in the various samples. Histomorphometry was used to demonstrate and quantify bone formation. RESULTS: After 2 weeks, the BMP-containing bioimplants had produced more new bone than any of the other materials. Particulated autogenous bone grafts produced less new bone initially (after 2 weeks), but the amount of bone produced by these grafts gradually increased, to levels comparable to the BMP-containing bioimplants by 8 weeks. For groups in which the poloxamer gel was used as a carrier for BMP or where BMP was used in combination with DBM, the amount of bone generated by 8 weeks was similar to that produced by autogenous bone. CONCLUSION: The rabbit maxillary sinus model allowed evaluation of multiple types of bioimplants that could be suitable for peri-implant maxillary reconstruction. BMP-containing bioimplants demonstrated promise as alternatives to autogenous bone grafts for sinus-augmentation procedures. These bioimplants had more rapid initial bone production than all other materials, including autogenous bone. In the future, such biomaterials may enable earlier placement of dental implants into augmented maxillary sinuses.

Sialometaplasia of the soft palate in a 2-year-old girl.

A case of sialometaplasia of the soft palate is reported in a 2-year-old girl three months after she had an adenoidectomy. Dental practitioners should be aware of the possible causes of intraoral swellings in both children and adults. The appearance of some conditions in children may differ from their characteristic appearance in adults. Necrotizing sialometaplasia may appear as an aggressive-looking lesion in an adult, possibly resembling squamous cell carcinoma. In the young patient reported here, frank necrosis was not evident from clinical or histological examination. Necrosis may not be part of the presentation of sialometaplasia in such young children.

Comparison of platelet-rich plasma, bovine BMP, and rhBMP-4 on bone matrix protein expression in vitro.

This study investigated the potential use of platelet-rich plasma (PRP) in conjunction with mRNA expression of bone matrix proteins using bioassay and RT-PCR comparing bovine bone morphogenetic proteins (BMP), recombinant human BMP-4 (rhBMP-4) during rat bone marrow stromal cell (Mesenchymal Stem Cell) differentiation at 14 days. The results showed that all three growth factors were associated with significantly elevated alkaline phosphatase activity. PRP and bovine BMP resulted in increased protein content. The mRNA of type I collagen was expressed with all three growth factors and remained consistently elevated. Osteopontin was observed with PRP from days 1 to 7; bone sialoprotein expression was detected on days 1 and 3. PRP, bovine BMP and rhBMP-4 enhanced the steady-state expression of PDGF-A as time-dependent to day 14 and in PRP was the strongest. PTHr was expressed at days 1 and 5. Vascular endothelial growth factor expression was the most highly expressed after day 3. These findings suggest that PRP increases mRNA expression of bone matrix protein, enchances osteogenesis and angiogenesis in vitro.

Induction of bone matrix protein expression by native bone matrix proteins in C2C12 culture.

OBJECTIVE: To study the expression of bone matrix protein (BMP) induced by bovine bone morphogenetic proteins (BMPs) in vitro. METHODS: Type I collagen, osteopontin (OPN), osteonectin (ON), osteocalcin (OC), and bone sialoprotein (BSP) were detected by immunohistochemistry in C2C12 cultured from day 1 to day 28. RESULTS: The signaling of bone matrix protein expression became weaker except for type I collagen, OC and BSP after 5 days. Fourteen days after culture, the positive signaling of type I collagen, OPN, ON, OC, and BSP was gradually declined, and could be detected significantly as compared with that of the negative control on day 28. BMP assay showed that the alkaline phosphatase (ALP) activity was higher in C2C12 culture than in the control during the 14-day culture. Also, total protein and DNA significantly increased during the 14-day culture. High levels of ALP were seen in preosteoblasts and osteoblasts in vivo and in differentiating osteoblasts in vitro. ALP was well recognized as a marker reflecting osteoblastic activity. CONCLUSION: Native bovine BMP induces conversion of myoblasts into osteoblasts, produces type I collagen, and plays significantly role in osteoinduction and bone matrix mineralization of C2C12 in vitro.

Pathologic fracture of the mandible caused by metastatic follicular thyroid carcinoma.

A pathologic fracture may be an acute event or a chronic long-standing ill-defined problem, and the causes are numerous. The dental practitioner may be the first health care practitioner to see a patient with a pathologic fracture of the jaw. This case report is intended to inform dental practitioners about pathologic fractures and the need for prompt referral to minimize patient suffering.

Combining adipose-derived stem cells, resorbable scaffolds and growth factors: an overview of tissue engineering.

Interdependency exists between adipogenesis, the formation of fat tissue from stem cells, and osteogenesis, the formation of bone from its stem-cell precursors. Adipose-derived adult mesenchymal stem cells may be useful for future bone regeneration and tissue engineering. This review discusses potential future relationships between autogenous adipose-derived stem cells, growth factors and resorbable scaffolds for future tissue-engineering applications.

Reconstruction of 10 major mandibular defects using bioimplants containing BMP-7.

PURPOSE: The limitations and morbidity associated with autogenous bone grafting have driven the search for predictable bone substitutes and bioimplants. A novel method of reconstruction was tested in this case series. MATERIALS AND METHODS: Ten patients with major mandibular defects following resection of biopsy-proven ameloblastoma lesions or osteomyelitis of the mandibular body or ramus were included in this study. The resection defects were spanned with rigid reconstruction plates to hold the remaining mandibular segments in the correct position. The defects were filled with a bioimplant containing bone morphogenetic protein-7 (BMP-7) in a demineralized bone matrix (DBM) suspended in a reverse-phase medium to effect sustained BMP delivery. RESULTS: The postoperative course for all 10 patients was uneventful. Radiographic evidence of mandibular bone formation was found in all cases. At the end of 1 year, functional and esthetic reconstruction of the mandible was complete. CONCLUSION: Bioimplants containing BMP-7 in DBM suspended in a reverse phase medium were successful in restoring major mandibular defects in nonirradiated beds in this series of 10 patients.

Juvenile idiopathic arthritis: a chronic pediatric musculoskeletal condition with significant orofacial manifestations.

Juvenile idiopathic arthritis (JIA), a broad term that describes a clinically heterogeneous group of arthritides of unknown cause, begins before 16 years of age. The hallmark feature of JIA is chronic inflammation of the joints, but the term encompasses several disease categories. The cause of JIA is still poorly understood and none of the available drugs for JIA can cure the disease. However, the prognosis has greatly improved as a result of progress in disease classification and management. The dental practitioner should be familiar with the symptoms and oral manifestations of JIA to help manage this disease.

Prevention of infective endocarditis: revised guidelines from the American Heart Association and the implications for dentists.

Infective endocarditis is a rare but life-threatening microbial infection of the heart valves or endocardium, most often related to congenital or acquired cardiac defects. The American Heart Association (AHA) recently updated its recommendations on prophylaxis during dental procedures. The revisions will have a profound impact on both the patient and the dental practitioner. The purpose of this paper is to review the pathogenesis and clinical presentation of infective endocarditis and discuss the 2007 AHA guidelines and their implications for dentists.

Simple preservation of a maxillary extraction socket using beta-tricalcium phosphate with type I collagen: preliminary clinical and histomorphometric observations.

Alveolar atrophy following tooth extraction remains a challenge for future dental implant placement. Immediate implant placement and postextraction alveolar preservation are 2 methods that are used to prevent significant postextraction bone loss. In this article, we report the management of a maxillary tooth extraction socket using an alveolar preservation technique involving placement of a cone of beta-tricalcium phosphate (beta -TCP) combined with type I collagen without the use of barrier membranes or flap surgery. Clinical examination revealed solid new bone formation 9 months after the procedure. At the time of implant placement, histomorphometric analysis of the biopsied bone showed that it contained 62.6% mineralized bone, 21.1% bone marrow and 16.3% residual beta -TCP graft. The healed bone was able to support subsequent dental implant placement and loading.

Comparison of titanium and resorbable copolymer fixation after Le Fort I maxillary impaction.

INTRODUCTION: Advances in skeletal stabilization techniques have led to the use of titanium devices for rigid fixation. Their advantages include strength and skeletal stability, but they also have disadvantages. The purpose of this study was to investigate the stability of a resorbable copolymer as a potential alternative to titanium for fixation of Le Fort I maxillary impaction. METHODS: Fifty consecutive patients underwent maxillary impaction with nonsegmental monopiece Le Fort I osteotomy. Twenty-five patients were treated with titanium fixation; 25 patients were treated with resorbable copolymer fixation (82% poly-L-lactic acid: 18% polyglycolic acid). Lateral cephalograms were obtained 1 week preoperatively, 1 week postoperatively, and a minimum of 8 months postoperatively. Linear and angular measurements were recorded digitally to evaluate 2-dimensional skeletal changes. RESULTS: Statistical analysis showed no significant radiographic differences (P <0.05) in long-term stability in or between the 2 groups. No clinical or radiographic evidence of wound healing problems was noted. CONCLUSIONS: These results support the use of resorbable copolymer fixation for Le Fort I impaction as a viable alternative to titanium fixation.

Effectiveness of 2 scavenger mask systems for reducing exposure to nitrous oxide in a hospital-based pediatric dental clinic: a pilot study.

Chronic exposure to elevated ambient air levels of nitrous oxide during nitrous oxide/ oxygen (N2O/2) sedation can result in deleterious side effects to dentists and auxiliary staff. A sampling survey was done in the outpatient dental clinic at the Hospital for Sick Children to determine whether airborne nitrous oxide (N2O) gas concentrations were within established regulatory limits. The effectiveness of 2 scavenger mask systems, the Matrix Medical single-mask system and the Porter/Brown double-mask system, for reducing airborne contamination in a clinical environment during the treatment of pediatric dental patients was compared in a pilot study. The results indicated that the double-mask system more effectively minimized N2O exposure during N2O/O2 sedation of outpatients for a variety of clinical pediatric dental procedures.

The lingual splint: an often forgotten method for fixating pediatric mandibular fractures.

Maxillofacial fractures are uncommon in the pediatric population, and their treatment is unique due to the psychological, physiological, developmental and anatomical characteristics of children. We present the case of a boy who was treated in an outpatient dental clinic using a lingual splint for the reduction, stabilization and fixation of a mandibular body fracture. This technique is a reliable, noninvasive procedure that dentists may consider in selected cases by referral to an oral and maxillofacial surgeon. It also limits the discomfort and morbidity that can be associated with maxillomandibular fixation or open reduction and internal fixation in pediatric patients.

Sialometaplasia of the soft palate in a 2-year-old girl.

A case of sialometaplasia of the soft palate is reported in a 2-year-old girl 3 months after she had an adenoidectomy. Dental practitioners should be aware of the possible causes of intraoral swellings in both children and adults. The appearance of some conditions in children may differ from their characteristic appearance in adults. Necrotizing sialometaplasia may appear as an aggressive-looking lesion in an adult, possibly resembling squamous cell carcinoma. In the young patient reported here, frank necrosis was not evident from clinical or histological examination. Necrosis may not be part of the presentation of sialometaplasia in such young children.