[Maxillofacial gunshot injuries in hostility activities in 2000-2003]

The management of facial gunshot wounded patients requires the coordination of multiple surgical disciplines to optimize the functional and cosmetic outcome while minimizing overall morbidity and mortality. All reports indicate that early management of these patients must focus on the basis of resuscitation, with major attention given to the status of maintaining the airway, hemostasis and hemodynamic resuscitation. Subsequent management of these patients becomes more controversial in terms of surgical reconstruction: immediate or delayed. Involvement of the use of suicide bombers, the type of weapons used in the last 2 years were different than previously described. The injuries were inflicted by explosives mixed with nails bolts and stones, which caused different kinds of wounds ever described. Numerous series in the literature advocate early aggressive intervention of one-stage reconstruction of all involved structures. However, several series published in the literature favor a more conservative approach, some of them even advocating non-operative management of these injuries. We concluded that a delay in final reconstruction of facial fractures in the critically ill patient has an acceptably low complication rate and may be advantageous in decreasing operative risk. A carefully planned reconstruction schedule is required to achieve satisfactory function and appearance. It is our purpose in this report to indicate the difference of the gunshot wounds in the last 2 years of the hostilities in this part of the world and emphasize the function of the Oral & Maxillofacial Surgeons in treating these patients.

[The overlooked chin trauma in children]

Children seldom experience major facial trauma. However, minor injuries such as facial lacerations, abrasions and dental trauma are more common and naturally get less attention. Children with TMJ trauma usually present with pain, limited jaw movement and even malocclusion. However, these findings are not always recognized and sometimes get overlooked when chin laceration is the only sign. Plain x-rays can contribute to the diagnosis but in many cases are inconclusive and are difficult to interpret. Often, there is a diagnostic dilemma, especially when the clinical findings are not clear and normal occlusion is hard to restore. We present 3 out of 12 children in whom we diagnosed condylar head fracture following minor facial trauma. All children had normal physiological occlusion. Most of them had mild clinical signs such as limited mouth opening, pain and tenderness upon palpation of the joint. Routine plain films were not conclusive. The diagnosis was made or confirmed with CT scan. Early diagnosis of TMJ fracture in children is mandatory for the prevention of long term functional and esthetically debilitating sequela.

CONCLUSION

A thorough clinical examination and normal occlusion do not rule out condylar head fracture after chin trauma. Plain films are of limited value in the diagnosis of such fractures. CT should be considered for the evaluation of these children.

Structure-bioactivity of C-terminal pentapeptide of osteogenic growth peptide [OGP(10-14)]

The amino acid sequence of osteogenic growth peptide (OGP) consists of 14 residues identical to the C-terminal tail of histone H4. Native and synthetic OGP are mitogenic to osteoblastic and fibroblastic cells and enhance osteogenesis and hematopoiesis in vivo. The C-terminal truncated pentapeptide of OGP, H-Tyr-Gly-Phe-Gly-Gly-OH [OGP(10-14)], is a naturally occurring osteoblastic mitogen, equipotent to OGP. The present study assesses the role of individual amino acid residues and side chains in the OGP(10-14) mitogenic activity which showed a very high correlation between osteoblastic and fibroblastic cell cultures. Truncation of either Tyr10 or its replacement by Ala or D-Ala resulted in substantial, but not complete, loss of activity. Nevertheless, only a small loss of activity was observed following removal of the Tyr10 amino group. No further loss occurred consequent to the monoiodination of desaminoTyr10 on meta-position. However, a marked decrease in proliferative activity followed removal of the Tyr10 phenolic or the Phe12 aromatic group. Loss of activity of a similar magnitude also occurred subsequent to replacing Gly11 with L- or D-Ala. Approximately 50% loss of mitogenic activity occurred subsequent to truncation of Gly14 or blocking the C-terminal group as the methyl ester. All other modifications of the C-terminus and L- or D-Ala substitution of Gly13 resulted in 70-97% decrease in activity. Collectively, these data suggest that the integrity of the pharmacophores presented by Tyr and Phe side chains, as well as the Gly residues at the C-terminus, are important for optimal bioactivity of OGP(10-14).

Isolation of mitogenically active C-terminal truncated pentapeptide of osteogenic growth peptide from human plasma and culture medium of murine osteoblastic cells

The osteogenic growth peptide (OGP) is a 14-amino acid stromal cell mitogen that stimulates in vivo osteogenesis and hematopoiesis. In the blood circulation and cell culture conditioned medium immunoreactive OGP (irOGP), identified using antibodies raised against the OGP C-terminal region, presents free and bound forms. The bound form consists entirely of the full length peptide. The present study was designed to investigate the identity of free irOGP under nondenaturing conditions. Fresh human serum and culture medium conditioned with murine osteoblastic MC3T3 E1 cells were fractionated using ultrafiltration (3000 molecular weight cut-off). Hydrophobic chromatography of the ultrafiltrate, immunoscreening of chromatographic fractions with antibodies directed against the OGP C-terminal region and amino acid sequencing of immunoreactive peaks demonstrated the presence of two mitogens, the full length OGP and a C-terminal truncated form, OGP(10-14). The OGP(10-14) derived from both serum and conditioned medium, as well as the synthetic pentapeptide [sOGP(10-14)], shared the in vitro OGP proliferative activity. However, in a competitive binding assay, devised to assess the OGP-OGP binding protein (OGPBP) complex formation, sOGP(10-14) failed to compete out radiolabeled OGP from the complex. It is concluded that OGP(10-14) is a naturally occurring human and murine mitogen. In addition, the data suggests that the OGP(10-14) is generated from OGP by proteolytic cleavage upon dissociation of the OGP-OGPBP complexes.

Surgical management of temporomandibular joint ankylosis type III by retaining the displaced condyle and disc

PURPOSE

This article proposes a hypothesis regarding the value of saving the fractured condyle and disc in their displaced position in ankylosis type III for optimal temporomandibular joint (TMJ) function and growth, and describes four cases treated in this manner.

PATIENTS AND METHODS

Four patients (three females and one male, 9 to 48 years old) with TMJ ankylosis type III of 3 to 8 years' duration, a maximal mouth opening of 15 to 19 mm, and severely limited lateral and protrusive movements were treated. The ankylosed sites were resected, leaving the displaced condyle and disc in their medial position.

RESULTS

Fifteen to 60 months after surgery, the patients had a maximal mouth opening of 44 to 50 mm, as well as better contralateral and protrusive movements. In addition, two young patients (9 and 11 years old) showed an improved facial symmetry.

CONCLUSIONS

Treatment of patients with type III TMJ ankylosis should involve retention rather than removal of the displaced condyle and disc. The condyle and disc are left untouched in their precarious medial position so as to provide normal function and growth.

Isolation of osteogenic growth peptide from osteoblastic MC3T3 E1 cell cultures and demonstration of osteogenic growth peptide binding proteins

The osteogenic growth peptide (OGP) was recently characterized in regenerating bone marrow. In experimental animals in increases osteogenesis and hemopoiesis. In stromal cell cultures OGP stimulates proliferation, alkaline phosphatase activity, and matrix mineralization. OGP in high abundance is present in normal human and animal serum mainly complexed to OGP binding protein (OGPBP) or proteins. Here we show the presence of two OGPBPs, OGPBP-1, and OGPBP-2, in cultures of osteoblastic MC3T3 E1 cells. Immunoreactive OGP (irOGP) also accumulates in the medium of these cultures and in cultures of NIH 3T3 fibroblasts. A large amount of irOGP was released by heat inactivation of OGPBP-2 and purified by ultrafiltration and hydrophobic HPLC. The purified irOGP was identical to OGP obtained previously from rat regenerating bone marrow and human serum in terms of its amino acid sequence, immunoreactivity, and mitogenicity. Osteoblastic and fibroblastic cell proliferation can be arrested by anti-OGP antibodies and rescued by exogenous OGP, indicating that in the absence of serum or other exogenous growth stimulators the endogenously produced OGP is both necessary and sufficient for baseline proliferation. The OGP production is up- and down-regulated, respectively, by low and high doses of exogenous OGP in a manner consistent with an autoregulated feedback mechanism. The most effective OGP dose in MC3T3 E1 cells is at least two orders of magnitude lower than that in non-osteoblastic cell systems. This differential sensitivity of the osteoblastic cells could result in a preferential anabolic effect of OGP in bone.

Cleidocranial dysplasia: Part 2--Treatment protocol for the orthodontic and surgical modality

The principles on which the present approach to the treatment of cleidocranial dysplasia are based were stated in part 1 of this article. Comparison was made with two other methods and the advantages of the present method were described in terms of (a) how this method is adapted to the clinical features of the condition, (b) when surgical intervention is appropriate, (c) how the dynamic appliance system may be adapted to the changing environment as more teeth erupt, and (d) the importance of rapidly bringing about the eruption of the anterior teeth. The practical aspects of the treatment are now described step-by-step with illustrations taken from the treatment of several different patients.

Cleidocranial dysplasia: Part 1--General principles of the orthodontic and surgical treatment modality

Over several decades, occasional reports of dental treatment provided by an individual practitioner to patients suffering with cleidocranial dysplasia have appeared in the literature. In the past, the main treatment was prosthetic replacement. Orthodontic treatment has only recently been considered as a serious treatment option, with success being described in several aspects of this treatment modality, in published individual case reports. Given the rarity of the condition, guidelines for the treatment of cleidocranial dysplasia are difficult to find in the literature, because few practitioners have treated enough cases to be in a position to make such recommendations. Two different approaches have been proposed in the past and are discussed here. The relative advantages of a third approach are expounded in detail.

Osteogenic growth peptide increases blood and bone marrow cellularity and enhances engraftment of bone marrow transplants in mice

The osteogenic growth peptide (OGP) was characterized recently in regenerating bone marrow (BM) and normal serum. In vitro, the OGP regulates stromal-cell proliferation and differentiated functions. In vivo, an increase in serum OGP accompanies the osteogenic phase of postablation BM regeneration. The present results in normal mice show that OGP induces a balanced increase in WBC counts and overall BM cellularity. In mice receiving myeloablative irradiation and syngeneic or semiallogeneic BM transplants, OGP stimulates hematopoietic reconstruction and doubles the survival rate; these effects are dependent on initiating the OGP administration before irradiation. Chimerism measurements in semiallogeneic graft recipients suggest no preferential effect of OGP on residual host cells. The data implicate OGP in the acceleration of hematopoiesis secondary to expansion of the stromal microenvironment and/or enhancement of stroma-derived signals to stem cells. The low-dose effectiveness of OGP is explained by the demonstration of an autocrine positive feedback loop that together with the OGP-binding protein sustains high serum levels of the peptide. A potential OGP-based treatment in combination with chemoradiotherapy is attractive because of the OGP-induced balanced multi-lineage enhancement of hematopoiesis and possible replacement of expensive recombinant cytokines by a readily synthesized peptide.

Attachment bonding to impacted teeth at the time of surgical exposure

This study examines the relative success of bonding an attachment to an impacted tooth at the time of surgical exposure, compared with placing it on a subsequent occasion. In addition, the relative merits of various attachments, the choice of bonding site and whether or not pumice prophylaxis is necessary, were tested. The results showed that bonding at the time of exposure is superior to its performance at a later date, that the use of an eyelet attachment has a lower failure rate than the use of a conventional bracket, that the palatal aspect offers the poorest bonding surface and that pumicing the exposed tooth offers no advantage over immediate etching of the exposed enamel. The results of this study refute the view that the circumstances prevalent at the time of surgical exposure are not conducive to the reliable bonding of an attachment to an impacted tooth.

Structural and functional characterization of osteogenic growth peptide from human serum: identity with rat and mouse homologs

The osteogenic growth peptide (OGP) was recently characterized in regenerating bone marrow. In experimental animals, OGP increases osteogenesis. Immunoreactive OGP (irOGP) in high abundance was demonstrated in normal animal serum mainly as an OGP-OGP-binding protein (OGPBP) complex. Here we show the presence of an OGP-OGPBP system in normal human serum. The total irOGP content, of which the bound peptide comprises at least 80-90%, ranged from 480-4460 mumol/L, several orders of magnitude higher than that of other regulatory polypeptides. The steady state/total irOGP ratio declined between 23 and 49 yr of age. The bound irOGP, purified by boiling, ultrafiltration, and hydrophobic high pressure liquid chromatography, was identical to OGP obtained previously from rat regenerating marrow and mouse stromal cell cultures in terms of its amino acid sequence, immunoreactivity, and mitogenicity. These data demonstrate the usefulness of our immunoassay to measure circulating OGP. More importantly, the identity of the human OGP with that of other species indicates the peptide's evolutionary conservation and, thus, its biological importance. The natural occurrence of OGP in man signifies its potential role in the prevention of bone loss and rescue of bone mass, especially in osteoporosis.

Mitogenic action of osteogenic growth peptide (OGP): role of amino and carboxy-terminal regions and charge

We have recently reported the discovery of a 14-amino-acid osteogenic growth peptide (OGP). In vivo OGP increases bone formation and trabecular bone density. Physiologically it is found in serum complexed to an OGP binding protein (OGPBP). In vitro OGP has a biphasic effect on osteoblastic MC 3T3 E1 and fibroblastic NIH 3T3 cell proliferation; at low concentrations (0.01-1.0 and 1.0-100.0 pM, respectively) it is highly stimulatory with an inhibition at higher doses. To assess possibilities of labeling synthetic OGP to obtain radio- or fluorescent ligands, OGP analogues were extended at the N- or C-termini with Cys or Cys(S-NEtSucc) or the OGP Tyr-10 replaced by 3-I(Tyr). All analogues with N-terminal modifications, as well as the [Cys15]OGP-NH2 retained the OGP-like dose-dependent effect on proliferation of the MC 3T3 E1 and NIH 3T3 cells, although the magnitude of stimulation was lower, approx. 2/3 that of the native-like synthetic OGP. The [Cys15(S-NEtSucc)]OGP-NH2 and [3-I(Tyr10)]OGP shared only the inhibitory activity of OGP. This suppression is further shared by a number of other positively and negatively net charged, but not net neutral, peptides. Both N-terminal-modified analogues displayed a decreased binding activity to the OGPBP. All analogues except reverse OGP, [3-I(Tyr10)]OGP and [Cys15(S-NEtSucc)]OGP-NH2 reacted with anti-OGP antibodies. These data are not only important for labeling purposes but suggest a respective role for the OGP N-and C-terminal regions in binding to the OGPBP and putative OGP receptor. It appears that the OGP proliferative activity represents the net effect of stimulation specific to the OGP structure and nonspecific inhibition associated with the peptide's high positive net charge.

Histone H4-related osteogenic growth peptide (OGP): a novel circulating stimulator of osteoblastic activity

It has been established that regenerating marrow induces an osteogenic response in distant skeletal sites and that this activity is mediated by factors released into the circulation by the healing tissue. In the present study we have characterized one of these factors, a 14 amino acid peptide named osteogenic growth peptide (OGP). Synthetic OGP, identical in structure to the native molecule, stimulates the proliferation and alkaline phosphatase activity of osteoblastic cells in vitro and increases bone mass in rats when injected in vivo. Immunoreactive OGP in high abundance is present physiologically in the serum, mainly in the form of an OGP-OGP binding protein complex. A marked increase in serum bound and unbound OGP accompanies the osteogenic phase of post-ablation marrow regeneration and associated systemic osteogenic response. Authentic OGP is identical to the C-terminus of histone H4 and shares a five residue motif with a T-cell receptor beta-chain V-region and the Bacillus subtilis outB locus. Since these latter proteins have not been implicated previously in the control of cell proliferation or differentiation, OGP may belong to a novel, heretofore unrecognized family of regulatory peptides. Perhaps more importantly, OGP appears to represent a new class of molecules involved in the systemic control of osteoblast proliferation and differentiation.

The diagnostic value of computed tomography in temporomandibular joint synovial chondromatosis

Synovial chondromatosis of the temporomandibular joint was diagnosed and location of dens particles was assessed by means of computed tomography. Based upon the data collected, the joint was operated conservatively and most of the calcifications were removed leaving the patient symptom free. The importance of an accurate preoperative diagnosis of synovial chondromatosis by use of CT scan is stressed in view of numerous unnecessary condylectomies and parotidectomies reported in the literature.

Effect of demineralized bone powder on osteoblast-like cells in culture. A potential rapid quality control assay

Demineralized bone powder (DBP) has been shown to induce osteogenesis in a variety of bone defects and extra-osseous sites. Previous investigations have been carried out in animal models which are time-consuming and expensive. We studied the effect of DBP on well-established populations of osteoblast and non-osteoblast-like cells in culture to establish an inexpensive, efficient and reliable assay for bone induction. DBP and BP (non-demineralized powder), of particle size 38-53 microns, were prepared from rat long bones. ROS (rat osteosarcoma) 17/2.8 and ROS 24/1 cell lines were subcultured weekly. For both 17/2.8 (well differentiated) and 24/1 (poorly differentiated) cells, proliferation, i.e. cell count, was significantly greater in DBP enriched medium when compared with control or medium with BP. Cell counts for wells with BP were no different from controls. The increased cell count in DBP-enriched medium was significant on days 2-5 (peak effect 2-3 days). Alkaline phosphatase production reached peak levels after day 3 when proliferation was beginning to taper off. In this study a consistent increase in osteoblast proliferation and alkaline phosphatase production under the influence of DBP was demonstrated. The tissue culture assay for proliferation must now be correlated with bone induction in vivo. In future, the method may be useful for investigating the mechanism of bone induction.

Submandibular tuberculous lymphadenitis (scrofula): report of two cases

Two cases of scrofula are presented. These cases were very different in terms of age of the patient, duration of the lesion, and the clinical course. The final diagnosis was based on the histologic findings and tuberculin tests.

Further characterization of osteogenic-cell growth promoting activity derived from healing bone marrow

During its osteogenic phase, post-ablation regenerating bone marrow produces bone promoting activity to osteogenic cells. In the experiments reported, activity derived from (rat) healing bone marrow conditioned medium (HBMCM) after boiling was analyzed using chromatography on heparin-Sepharose. The activity in HBMCM was shown to be divided among at least six independent activities that stimulated DNA synthesis rates is osteogenic rat osteosarcoma (ROS) cells. Three activities resolved when heparin-Sepharose was washed isocratically with phosphate buffered saline. Two of these were resistant to reduction and acidification and their effect was considerably more potent in osteogenic than non-osteogenic ROS cells. Three additional activity peaks recovered when the heparin-Sepharose column was pumped with an NaCl gradient. Two of them eluted at 0.3 and 0.65 M NaCl, affected osteogenic and non-osteogenic ROS cells to a similar extent and may be attributed to platelet-derived growth factor. A third peak, resolved at 1.2 M NaCl, implies the residual activity of acidic fibroblast growth factor that persisted after boiling of the conditioned medium. It is concluded that the activity profile of HBMCM reflects the in vivo situation where the osteogenic phase of marrow regeneration is probably regulated by multiple growth factor species.

Regenerating bone marrow produces a potent growth-promoting activity to osteogenic cells

It is well documented that injury to bone marrow is followed by an osteogenic phase that precedes the complete tissue regeneration. We have recently shown that postablation healing of bone marrow in rat tibiae is associated with a systemic increase in osteogenesis. It was hypothesized that a growth factor(s) with an effect on osteogenic cells is produced in the healing limb, is transferred to the blood circulation, and enhances osteogenesis systemically. To test growth factor production, healing bone marrow-conditioned medium was prepared with tissue separated from rat tibias during the osteogenic phase and assayed for enhancement of mitogenic activity in culture of osteogenic rat osteosarcoma cells (ROS 17/2). Partial purification of healing bone marrow-conditioned medium-derived growth factor(s) consisted of gel filtration on Sephadex G-25, boiling, chromatography on heparin-Sepharose, and gel filtration on Sephadex G-75. Mitogenic activity eluted in the void volume of the Sephadex G-25 column (mol wt greater than 5,000). Potent activity resolved from heparin-Sepharose with PBS, and on filtration by Sephadex G-75 this activity recovered in 3 peaks with mol wt estimates of 35,000, 19,000, and less than 10,000. The partially purified factor also showed considerable stimulatory effect on DNA synthesis in osteoblastic fetal rat calvarial cells and on in vitro elongation of fetal long bone; it had only a small effect on nonosteoblastic ROS and fetal rat calvarial cells. These data indicate that healing bone marrow produces growth factor activity with a preferential effect on osteogenic cells. It is suggested that local growth factors have a role as mediators in the sequence of events whereby bone marrow expresses its osteogenic potential. During postablation healing of bone marrow these factors may also function as systemic promoters to osteogenic cells.

Mitogenic response of cells in culture to demineralized bone matrix

In this study the mitogenic effect of demineralized bone powder (DBP) on cells in tissue culture was evaluated. The cells studied have osteoblastic properties. At a DBP concentration of 100 micrograms/well, rat osteosarcoma cells (ROS) 17/2.8 cells, ROS 24/1 cells, and periosteal fibroblasts (POF) all showed a significant increase in proliferation in comparison to controls. The peak effect was on day two for ROS 17/2.8 (125% of control), on day three for ROS 24/1 (139% of control), and on day four for POF (145% of control). The results indicate that this in vitro system may be useful for evaluating the osteoinductive activity of DBP preparations.

Mental nerve neuropathy associated with compound odontoma

An instance of anesthesia of the lower lip caused by a compound odontoma in the mental foramen region is described. Removal of the odontoma was followed by a full recovery of the sensation.

Characteristics of a neutral amino acid transport system (system A) in osteoblastic rat osteosarcoma cells

Transport of alpha-aminoisobutyric acid (AIB) in the clonal, osteoblastic-like cell line, ROS 17/2, was characterized. AIB transport was time-, temperature- and Na+-dependent. Both ouabain and monensin inhibited AIB transport in these cells. AIB uptake followed Michaelis-Menten kinetics with an apparent Km = 0.57 mM and a Vmax = 4.07 nmol/30 min/plate. These characteristics are consistent with the presence of system A neutral amino acid transport in ROS 17/2 cells. Exposure of ROS 17/2 cells to either parathyroid hormone or dibutyryl cyclic AMP (db-cAMP), but not to dibutyryl cyclic GMP (db-cGMP), markedly stimulated AIB transport. This suggests that extracellular stimuli which enhance osteogenic responses in this cell type, coordinately upregulate system A transport.

Enhancement by extracts of mineralized tissues of protein production by human gingival fibroblasts in vitro

Non-confluent cell cultures were exposed to both guanidine and guanidine-EDTA extracts of cementum, dentine and alveolar bone, at concentrations from 2 to 50 micrograms/ml for 48 h. The cells were radioactively labelled during the last 24 h. Total protein production was measured via incorporation of radioactive proline; collagen production was estimated by digestion of the radioactive protein mixture with bacterial collagenase. All guanidine-EDTA extracts elicited statistically-significant increases in total protein production when compared to controls. At 50 micrograms/ml of extract, the increase in protein production was 340, 143 and 338 per cent for bone, cementum and dentine, respectively. Similar results were obtained for collagen production. Guanidine-EDTA extracts also stimulated an increase in the production of specific proteins, as ascertained by gel electrophoresis. In contrast, the guanidine extracts had no effect on either protein or collagen production. Thus the functions of gingival fibroblasts can be altered by proteins from associated mineralized tissues. Identification of such proteins and their biological functions would enhance knowledge of the mechanisms that regulate connective-tissue regeneration.

Hormone-responsive cells derived from human dental papilla: characterization in vitro and in vivo in diffusion chambers

Cells of the dental papilla are capable of odontoblastic, fibroblastic, and endothelial differentiation and formation of dentin and the dental pulp. In the present study dental papilla cells, obtained from human tooth buds (HDP cells), were cultured in vitro through 3 to 7 passages. After exposure to prostaglandin E2 there was a marked decrease in intracellular cyclic AMP (cAMP) levels as compared to hormone-free controls. Parathyroid hormone and calcitonin had stimulatory effects with 1 and 2 log increases in cAMP, respectively. The HDP cells showed moderate activity of alkaline phosphatase, 1 log higher than that of hamster kidney fibroblasts (BHK 13) and 1 log lower than that of osteoblastic osteosarcoma cells (ROS 17/2). When cultured for 4 or 8 wk in diffusion chambers (DC) implanted in athymic mice, many of the HDP cells underwent odontoblastic morphodifferentiation with very long, single processes extending into the matrix. This matrix contained banded and unbanded collagen fibers. Neither light nor electron microscopy of the DC content revealed mineral deposits. These results suggest that HDP cells have an intrinsic potential for partial odontoblastic differentiation; inductive signals like those originating from odontogenic epithelium are probably essential for the completion of hard tissue formation.

Stimulation of mannose incorporation into rat osteoblastic osteosarcoma cells by parathyroid hormone

Agents considered to alter cAMP accumulation in bone cells were evaluated for their effects on protein production and sugar incorporation by bone cells. Total protein production or mannose incorporation by cells and in media were measured by the amount of radioactivity incorporated into trichloroacetic-acid precipitable fractions. Incorporation of radioactive leucine into the cellular and secreted proteins was linear over 5 h; radioactive mannose incorporation was linear only up to 2 h. Cells were also incubated with selected agents and radioactive mannose or leucine for 2 h. Addition of parathyroid hormone (PTH), isoproterenol or dibutyryl cAMP to osteoblasts resulted in a significant increase in mannose incorporation; dibutyryl cGMP and butyric acid had no effect on mannose incorporation. None of the agents altered total protein production. Thus PTH stimulates mannose incorporation into osteoblasts and this effect is, at least in part, modulated by cAMP.

Inflammatory cells and bacteria in pericoronal exudates from acute pericoronitis

The present work is one in a series of studies carried out to verify the relationship between bacteria and gingival tissues in pericoronitis. Exudates from 6 cases of acute pericoronitis were examined by light and electron microscopy, including ultrathin sections and negative staining. While bacterial phagocytosis was prevalent in all the exudates studied, spirochetes, which were the predominant microorganisms, were not observed being phagocytized by PMNs or macrophages. The presence of spirochetes in pericoronitis as compared with acute necrotizing ulcerative gingivitis is discussed.

Formation of calcifying matrix by osteosarcoma cells in diffusion chambers in vivo

The potential of clonal rat osteosarcoma (ROS) cell lines to form mineralized matrices was assessed in diffusion chambers in vivo. Diffusion chambers were inoculated with osteoblastic (ROS 17/2 and its subclone ROS 17/2.8) and non-osteoblastic (ROS 24/1) clonal lines and implanted either intraperitoneally into athymic mice or subcutaneously into syngeneic ACI rats. Control chamber cultures of rabbit marrow or spleen cells were also incubated in athymic mice. Light and electron microscopy of chambers with ROS 17/2 and ROS 17/2.8 cells revealed production of mineralized matrices typical of osteosarcoma and characterized by abundance of collagen fibrils and associated mineralizing nodules. ROS 24/1 cells produced similar collagenous matrices, but these were devoid of mineral. The present experiments, carried out independently in two different laboratories, demonstrate the potential of ROS cells to produce a mineralized matrix. This corroborates previous studies on other osteoblastic features of these cell lines.

Pericoronitis: a reappraisal of its clinical and microbiologic aspects

Pericoronitis is an infectious disease of the operculum overlying an erupting or semi-impacted tooth. It manifests itself mainly in late adolescence and young adulthood and nearly always occurs around the lower third molar. The distinctive location, age, clinical picture, and link with predisposing factors warranted a reappraisal of pericoronitis and its etiology. Spirochetes and fusobacteria proved prevalent at all stages of the disease. The presence of these microbacteria may provide a clue as to the late appearance, particular location, and singular clinical picture of pericoronitis. The fact that spirochetes and fusobacteria are also found in acute necrotizing ulcerative gingivitis, and have been associated with alveolar osteitis, indicates a possible relationship between these disorders and pericoronitis.

Salivary calculi: ultrastructural morphology and bacterial etiology

Ultrastructural morphology of 16 salivary calculi was studied by means of transmission and scanning electron microscopy. The external surface was mostly globular or coarse, and on high magnifications and features could be divided into four main groups: a) amorphic calcified deposits covering extensive areas, b) other areas covered with crystals in a variety of arrangements, c) heavy accumulations of calcified rod-like and filamentouslike microorganisms, and d) platelet crystals in juxtaposition to calcified microorganisms in several areas. In most calculi the split area was found to be laminated. It is suggested that microorganisms have an important role in the formation and growth of salivary calculi.

Odontoma in the subcondylar region

An instance of a compound odontoma in the condylar process in a 24-year-old female is described. Location of odontomas in the coronoid or condylar processes were not reported. A hypothesis of migration of the third molar bud into the condylar region, an interfering local factor such as trauma or infection are suggested as aetiologic factors to the tumour in this case. Pre-operative radiographic localisation of the mass, are essential for treatment planning. An intra-oral approach was the treatment of choice.

Lymphosarcoma of the mandible associated with macroglobulinemia of Waldenström

Waldenström macroglobulinemia is a rare progressive immunoproliferative disorder involving lymphocytes and occasionally plasma cells. Unlike the multiple myeloma, this disease has minimal osseous lesions. Lesions in the jaws are very rare. This paper presents a case of lymphosarcoma in the mandible in a 68-year-old woman, who was diagnosed as suffering from Waldenström macroglobulinemia. The possibility of immunosuppression by Leukeran as an aetiologic factor causing the bone lesions is suggested.

The mural ameloblastoma: a review of the literature

Mural ameloblastomas are estimated to constitute 5% of all ameloblastomas. Although resembling the total ameloblastoma population in terms of predilections for sex and site, the average age of the patients with mural ameloblastoma, in comparison with the total group, was 21.8 vs 38.9 years. Eighty-five percent of the mural ameloblastomas were associated with follicular cysts, all of which were observed before the age of 30. The frequency of recurrence after simple enucleation of the cyst containing this lesion is considerably lower than that for ameloblastomas in general that are treated in a similar manner. Therefore, further and more extensive surgery for mural ameloblastoma is justified only in the event of recurrence.

The basal cell nevus syndrome associated with cleft lip and cleft palate: report of case

A case of basal cell nevus syndrome with multiple keratocysts, cleft lip and cleft palate, calcification of the falx cerebri, and late appearance of basal cell carcinoma is described.

Resorption of the crown in impacted maxillary canine. A clinical, radiographic and histologic study

Thirty-six maxillary impacted canines which showed coronary resorption were selected out of 252 impacted canines. Clinical, radiographic and histologic observations were performed. In the majority of the cases (31) a local inflammatory factor was present and only in five cases was the resorption idiopathic. The incidence of resorption was highest in the later decades of life. In all cases bone replacement was found.

Modification of the muco-periosteal flap design in anterior maxillary osteotomies

A modification of the mucoperiosteal flap planning for anterior maxillary osteotomy operations is suggested. This approach involves a total reflection of the labial mucoperiosteal flap, with the advantages of direct vision of the operative field thus providing easy and precise execution of the operative bony cuts, avoiding damage to the adjacent teeth and reduction of operating time. Sufficient blood supply to the mobilised segment is maintained through the palatal blood vessels. Corrective periodontal surgery may also be carried out at the same time.

Median mandibular cyst

Since the median mandibular cyst is an extremely rare lesion, there is difficulty in determining the nature and origin of this entity. An additional case of a median mandibular cyst is described and an attempt is made to clarify the confusion associated with the diagnosis of this lesion. After a review of the literature it is suggested that the median mandibular cyst is a much rarer entity than was previously believed.

Effect of local application of fluoride on healing of experimental bone fractures in rabbits

The effect of local application of low fluoride concentrations on the healing of experimental bone-radii fractures in 20 rabbits was examined. No external fixation was required after the osteotomy and gelfoam being used as a medium for fluoride application. Histologic mineral and mechanical strength measurements were carried out on the healing callus. There were no significant changes in the ashpercentage and the fluoride concentration of the ash between the experimental and control callus. A significantly higher percentage of ossified tissue was found in the fluoride treated callus. The breaking strength was found to be significantly higher in the bone fractures treated with fluoride, whereas there was no notable difference between the surface areas. It is postulated that the greater amount of ossified tissues, the differences in organization of the bone trabecules, and/or an improved mineral crystallinity may be responsible for this result.

The effect of long standing chronic mechanical irritation on the tongue of rats

The effect of long standing mechanical irritation of the tongue was studied in 100 young rats. This was effected by the protruding end of a twisted wire, ligated around the lower first molar and directed toward the later-ventral aspect of the tongue on one side, while the other side served as control. Groups of rats were killed after 3, 6, 9 and 12 months and the tongues were examined grossly and microscopically. Fibrous hyperplasia was observed in 48% of tongues in the 3-month group and increased to 79% in the 12-month group. Microscopically, epithelial changes were noted which included ulceration acanthosis and hyperkeratosis. In no instance was dyskeratosis or any other malignant change noted.

Scanning electron microscopy of dental calculus

The morphologic structure of anorganic dental calculus was studied by means of the scanning electron microscope. From surface observations, calculus is apparently composed of two components with distinguishable patters of calcification. One component is formed by the precipitation of minute calcific crystals on microorganisms and intermicrobial substances (plaque matrix). Such calcified masses, often spherical in shape, have a sponge-like appearance with empty spaces representing the former sites of entombed and degenerated organisms. Thus, intracellular calcification is not evident at this stage of calculus development. The other component, although having at least one common calcification front with the former, does not appear to be directly associated with microbial calcification. It exhibits a configuration of generally larger crystal growths of varying shapes and sizes. These two calcification patterns are comparable, both in distribution and size, to what has been observed by means of the transmission electron microscope, and what Schroeder has designated as "types A & B centers of mineralization," respectively. The calcific precipitation in type A centers have been identified by X-ray diffraction as hydroxyapatite. It is, therefore, speculated that the crystal patters in type B centers might represent other known forms of calcium phosphates present in calculus, such as octacalcium phosphate, whitlockite and brushite.