Effectiveness of operative treatment of internal orbital wall fracture with polydioxanone implant

Many implants, some made from teflon or silicone, have been used for internal orbital wall reconstruction. Late complications relating to use of such implants have been reported. In this prospective study a polydioxanone (PDS) implant absorbable in vivo was used for internal orbital wall reconstruction. Follow-up involved clinical examination, magnetic resonance imaging (MRI) and computerized tomography (CT). Clinical examinations were undertaken before operation and up to 36 weeks postoperatively. Sixteen consecutive patients (10 pure blow-out fractures, six with associated zygomatic fracture) took part in the study. Prevalences of diplopia, proptosis and enophthalmus were recorded during each follow-up examination. This study revealed no muscle entrapment within the fracture line. Although CT results confirmed bone growth in the internal orbital wall, shape was unsatisfactory, and orbital volume was not reduced. MRI revealed thick scar formations in six cases (37.5%), fibrotic sinuses filled with air or gas in three cases (19%) and a fibrotic sinus with fluid around the PDS in one case (6%). Our results suggest that use of PDS in reconstructing the internal orbital wall is inadvisable.

Disodium clodronate in the treatment of diffuse sclerosing osteomyelitis (DSO) of the mandible

Diffuse sclerosing osteomyelitis (DSO) of the mandible is a chronic condition, the cause of which is not known. Jaw pain, occurring irregularly, is a typical symptom. The aim of the study was to assess the effectiveness of disodium clodronate for relieving pain in patients with DSO. Disodium clodronate is a bisphosphonate used to treat diseases of bone and calcium metabolism. Ten DSO patients experiencing pain received disodium clodronate or placebo intravenously on a randomized double-blind basis. Both minimum (300 mg) and maximum (900 mg) doses were well tolerated. Disodium clodronate administration did not result in better immediate pain relief than placebo administration. However, 6 months after treatment there was a statistically significant difference in pain intensity between the groups, with the disodium clodronate group experiencing significantly less pain.

Focal sialadenitis in patients with ankylosing spondylitis and spondyloarthropathy: a comparison with patients with rheumatoid arthritis or mixed connective tissue disease

OBJECTIVES

To investigate the occurrence of and risk factors for focal sialadenitis in patients with rheumatoid arthritis (RA), mixed connective tissue disease (MCTD), ankylosing spondylitis (AS), and spondyloarthropathy (SpA).

METHODS

A total of 85 patients (25 with RA, 19 with MCTD, 19 with AS, 22 with SpA) participated in the study. Each patient filled out a questionnaire for eye and oral symptoms and for the use of medication, and was interviewed; other tests included Schirmer's test, laboratory tests, collection of unstimulated and stimulated whole saliva, and minor salivary gland biopsy. A focus score of > or =1 was regarded as an indicator of focal sialadenitis.

RESULTS

Focal sialadenitis was observed in 68% (57/84) of all patients. It affected 80% (20/25) of the patients with RA, 94% (17/18) of those with MCTD, 58% (11/19) of those with AS, and 41% (9/22) of those with SpA (chi(2) test, p=0.0013). Salivary secretion correlated negatively with the focus scores-that is, severity of focal sialadenitis. Patients with focal sialadenitis had both decreased salivary secretion and decreased tear secretion significantly more often than did patients without (chi(2) test, p=0.0074 and p=0.048 respectively). Patients with positive rheumatoid factor (RF), antinuclear antibodies (ANA), or SSA or SSB antibodies had sialadenitis significantly more often than did patients with negative antibodies. In the subgroup of patients with AS or SpA, no associations were found between focal sialadenitis and the presence of these antibodies.

CONCLUSION

In addition to patients with RA or MCTD, focal sialadenitis also affects a very high proportion of patients with AS or SpA. Focus scores are significantly higher in patients with RA or MCTD than in those with AS or SpA. A significant association exists between focal sialadenitis and RF, ANA, SSA and SSB. However, in the subgroup of patients with AS or SpA, no associations were found between focal sialadenitis and serological markers or clinical symptoms.

Differences between patients with or without the need for intensive care due to severe odontogenic infections

PURPOSE

Despite greatly improved dental health in industrialized countries, severe odontogenic infections still occasionally lead to hospitalization. The aim of the present study was to determine whether what symptoms, signs, or laboratory parameters on hospital admission were associated with the need for treatment in the intensive care unit (ICU).

PATIENTS AND METHODS

Over an 18-month period, 100 consecutive patients (59 male, 41 female) were included in the study. Twenty percent of the patients required ICU treatment because of cardiorespiratory problems or severe complications of their infection. Both ICU and non-ICU patients were examined clinically and blood samples were taken and studied in respect to several parameters associated with infection, including C-reactive protein (CRP) levels. The findings were analyzed statistically for differences between the groups.

RESULTS

No particular anamnestic background variable was associated with the need for intensive care. However, a particularly high CRP level on admission was found to be associated with a more severe course of the infection.

CONCLUSIONS

This study showed that determination of CRP levels may be useful in clinical decision-making in patients with severe odontogenic infections.

Amphiphile-induced vesiculation in aged hereditary spherocytosis erythrocytes indicates normal membrane stability properties under non-starving conditions

Aged HS erythrocytes with a defined primary defect in band 3 protein or ankyrin were incubated with amphiphiles (detergents) at sublytic concentrations (37 C, 60 min) or glucose-starved (37 C, 24 h). In line with previous studies, the release of AChE (exovesicles) from HS erythrocytes during glucose-starvation was significantly higher (11%) compared to that from control erythrocytes (1%). Control and HS cells responded, however, similarly to amphiphile-treatment (non-starving conditions). Amphiphiles induced similar types of shape alterations and a similar amount of AChE release (14-15%). Furthermore, the size and shape of amphiphile-induced exo- and endovesicles released from control and HS erythrocytes were similar. The results suggest that the stability properties of the membrane are not seriously disturbed in aged HS erythrocytes under non-starving conditions.

Condylar process fractures in children: a follow-up study of fractures with total dislocation of the condyle from the glenoid fossa

PURPOSE

The purpose of this study was to investigate the long-term clinical and radiologic outcome of nonsurgically treated, dislocated condylar fractures sustained during childhood.

PATIENTS AND METHODS

Dislocated condylar process fractures were diagnosed in 34 children aged 15 years or younger from 1980 to 1991. Of these, 26 had been treated nonsurgically and were asked to participate in a follow-up examination. Eighteen patients, representing 69% of the total sample, took part in the study. All patients underwent a clinical investigation with special emphasis on temporomandibular joint (TMJ) function. The patients also underwent a radiologic investigation, focusing on fracture remodeling and symmetry of the mandible.

RESULTS

After a follow-up period ranging from 4.8 to 16.4 years (mean, 8.6 years), 56% had some subjective symptoms, and 72% had some objective signs of TMJ dysfunction. In general, however, the symptoms and signs of dysfunction were very slight. No correlation was observed between the method of nonsurgical treatment and the clinical results. Radiologic investigation showed incomplete remodeling (76.5%) and asymmetry of the mandible (64.7%) in most patients. The asymmetry was slight, however, and could not be observed clinically.

CONCLUSIONS

Conservative treatment of dislocated condylar process fractures in children results in satisfactory long-term outcome of jaw function despite a high frequency of radiologically noted aberrations. Soft diet with immediate mobilization seems to be the treatment of choice.

Generation of hydroxyl radicals by the antiviral compound phosphonoformic acid (foscarnet)

Phosphonoformic acid (foscarnet) is an antiviral agent that is used to treat severe cytomegalovirus infections in AIDS patients. We demonstrate by using the ferrous iron indicator Ferrozine and ascorbic acid (vitamin C) that foscarnet can chelate ferric iron and form a redox-active iron complex. By using the hydroxyl radical indicator coumarin-3-carboxylic acid we found that the foscarnet-Fe3 complex formed can readily catalyze hydroxyl radical (.OH) generation by the Fenton reaction: (Fe2+ + H2O2-4Fe3+ + .OH + -OH) if hydrogen peroxide and ascorbic acid are present. Hydroxylation of coumarin-3-carboxylic acid could be blocked by addition of known hydroxyl radical scavengers such as mannitol, sucrose, glucose and dimethyl sulfoxide. Moreover, by using a DNA nicking assay, we found that foscarnet catalyzed hydroxyl radicals can induce single strand brakes in DNA. The potency of the hydroxyl radicals formed to induce damage could also be demonstrated in a phosphate-free buffer where the hydroxyl radicals formed attacked and liberated phosphate from the foscarnet molecule. Our results indicate that foscarnet catalyzed hydroxyl radical formation might take place during conditions where a peroxide generating system(s), vitamin C and transitions metals are present.

A comparative study on four screw-plate locking systems in sheep: a clinical and radiological study

Four mandibular screw-plate locking systems were studied in sheep. Three to four centimetres angular continuity resections of the mandible were performed and the defects bridged with pre-bent angular reconstruction plates fixed with four screws in the body part and three in the ramus. Each type was used four times. Clinical and radiological examinations were carried out 1 and 2 months later. All sheep were able to eat and ruminate normally throughout the postoperative period. Radiology revealed that 6/16 plates and 5/112 screws fractured during the follow-up period. In one type, no fracture occurred. Screw fracture was confined to just one reconstruction system. Six of 16 mandibles showed slight to moderate bone resorption under the plate. The results point to the internal shortcomings of the systems tested.

Poor dental status increases acetaldehyde production from ethanol in saliva: a possible link to increased oral cancer risk among heavy drinkers

Epidemiological data support evidence that poor dental status increases oral cavity cancer risk especially among heavy alcohol consumers, but the causality of this finding is unclear. The enzymatic conversion of ethanol by the physiological oral microflora may lead to an accumulation of the highly carcinogenic intermediate acetaldehyde. This study was conducted to evaluate the role of dental status on the microbial production of acetaldehyde from ethanol in saliva. The microbial acetaldehyde production from ethanol was related to the dental score in 132 volunteers. After adjustment for smoking, alcohol consumption, age and gender, poor dental status was shown to lead to an approximately twofold increase in salivary acetaldehyde production from ethanol (P=0.02). Our results could be an important factor underlying the role of poor dental hygiene and status in oral cancer risk associated with ethanol drinking.

Collagenases in different categories of peri-implant vertical bone loss

The loosening of dental implants is associated with peri-implant vertical bone loss. The mechanisms and mediators of this bone destruction are not known. To test the hypothesis that collagenase-2 and collagenase-3 might be markers or maybe even mediators in this process, we measured collagenase-2 (time-resolved immunofluorometric assay) and collagenase-3 (quantitative immunoblot) in peri-implant sulcus fluid in 49 implant sites in 13 patients. Vertical bone loss was graded as being < 1 mm, from 1 to 3 mm, or > 3 mm. The severity of inflammation, as rated according to Gingival Index, did not correlate with the category of bone loss (p > 0.05). Collagenase-2 and collagenase-3 were higher (p < 0.05) in the group which had lost > 3 mm of bone than in the two other groups. Gingival Index is not a clinically important marker for bone loss, but collagenase-2 and collagenase-3 in peri-implant sulcus fluid are. They might participate in peri-implant osteolysis.

Increased salivary acetaldehyde levels in heavy drinkers and smokers: a microbiological approach to oral cavity cancer

The pathogenetic mechanisms behind alcohol-associated carcinogenesis in the upper digestive tract remain unclear, as alcohol is not carcinogenic. However, there is increasing evidence that a major part of the tumour-promoting action of alcohol might be mediated via its first, toxic and carcinogenic metabolite acetaldehyde. Acetaldehyde is produced from ethanol in the epithelia by mucosal alcohol dehydrogenases, but much higher levels derive from microbial oxidation of ethanol by the oral microflora. In this study we investigated factors that might alter the composition and quantities of the oral microflora and, consequently, influence microbial acetaldehyde production. Information about dental health, smoking habits, alcohol consumption and other factors was obtained by a questionnaire from 326 volunteers with varying social backgrounds and health status, e.g. oral cavity malignancy. Paraffin-induced saliva was collected and the microbial production of acetaldehyde from ethanol was measured. Smoking and heavy drinking were the strongest factors increasing microbial acetaldehyde production. Whether poor dental status may alter local acetaldehyde production from ethanol remained unanswered. Bacterial analysis revealed that mainly gram-positive aerobic bacteria and yeasts were associated with higher acetaldehyde production. Increased local microbial salivary acetaldehyde production due to ethanol among smokers and heavy drinkers could be a biological explanation for the observed synergistic carcinogenic action of alcohol and smoking on upper gastrointestinal tract cancer. It offers a new microbiological approach to ethanol-associated carcinogenesis at these anatomic sites.

Oral health of patients scheduled for elective abdominal aortic correction with prosthesis

OBJECTIVE

to evaluate the frequency of potential oral foci of infection in patients scheduled for elective abdominal aortic surgery.

DESIGN

prospective clinical study.

MATERIALS

oral health and dentures of 50 patients (33 males and 17 females, mean age 65 years) were examined before aortic surgery.

CHIEF OUTCOME MEASURES

radiographic and clinical examination with special emphasis on identifying acute and chronic oral and ontogenic conditions which may contribute to aortic prosthesis infection.

RESULTS

eighty-two per cent of the patients had some oral infection foci. The mean number of remaining teeth in the cohort was 9.3, and 21% of these were potential infectious foci (62% in the patients). Twenty-six per cent of the patients suffered from oral Candida infection. Seventy-four per cent of the patients had total or partial dentures, 45% of which were ill-fitting and needed repair.

CONCLUSIONS

oral infectious foci occur frequently in patients needing aortic surgery. Untreated foci may contribute to aortic prosthesis infection. Preoperative oral evaluation and elimination of intraoral infection is recommended for patients scheduled for abdominal aortic repair.

Bioabsorbable plates and screws: Current state of the art in facial fracture repair

BACKGROUND AND OBJECTIVES

The use of bioabsorbable materials in craniomaxillofacial surgery began a new era in fracture fixation. The purpose of this paper is to review the historical perspectives and the current concept of bioresorbable materials in fracture fixation.

METHODS AND MATERIALS

The authors review the biochemistry and clinical characteristics of bioabsorbable polymers--polylactic acid (PLA), polyglycolic acid (PGA), polydioxanone (PDS), and their copolymers. Their use and clinical perspectives by the Helsinki (authors') group and other study groups are presented.

RESULTS AND CONCLUSIONS

These materials have proven to be safe in clinical applications. When manufactured with current technology, they are easy to handle. Economically, they are nearly equal to similar metal devices. The materials have met clinical success throughout the world, first in orthognathic surgery, followed by treatment of fractures of the upper facial skeleton and the mandible. Today, most maxillofacial fractures and osteotomies may be adequately fixed with bioabsorbable materials.

Detection of baculovirus-infected insect cells by flow cytometric side-scatter analyses

BACKGROUND

The baculovirus expression vector system (BEVS), utilizing the Autographa californica nuclear polyhedrosis virus (AcNPV), has turned out to be an attractive alternative for high-level expression (<600 mg/l) of recombinant proteins. However, there is a shortage of reliable methods for monitoring the infection process in situations where marker proteins cannot be used.

METHODS

Three recombinant baculoviruses, FastBac1-wtGFP, VTBac-GFP, and VL1392-hIL-2Ralpha, all having the genes inserted under the transcriptional control of the polyhedrin gene promoter of the Autographa californica nuclear polyhedrosis virus (AcNPV), were used to infect Spodoptera frugiperda (Sf9) and Mamestra brassicae (IZD-MB-0503) insect cells. The infection process of the recombinant baculoviruses was monitored by flow cytometric side-scatter and fluorescence intensity analyses over a period of 6-96 h.

RESULTS

A clear correlation between the side-scatter (SSC) signal and the relative fluorescence was observed for both of the infected cell lines, compared to noninfected cells. Comparison of SSC histograms from noninfected insect cells with cells infected with the nonfluorescent recombinant baculovirus VL1392-hIL-2Ralpha showed a clear increase of SSC for the infected cells.

CONCLUSIONS

The SSC parameter can therefore be utilized for flow cytometric monitoring of a baculovirus infection process in situations where suitable markers are not available.

Histological study of tissue reactions to epsilon-caprolactone-lactide copolymer in paste form

In previous studies, epsilon-caprolactone-lactide copolymer in solid form has been used in experimental animals as suture material, and as a biodegradable nerve guide. The aim of the study reported here was to assess tissue reactions to epsilon-caprolactone-lactide copolymer in paste form, histologically, and to compare bone healing at the sites of implantation versus that at control sites. The other purpose of the study was to evaluate the properties of the implanted material as a filling material for bone defects. Resorption time and intensity of inflammatory reaction were also evaluated. Material was implanted into the abdominal walls and femurs of 34 rats. Follow-up times were from 2 weeks to 1 year. The results showed that epsilon-caprolactone-lactide copolymer in paste form induces a severe inflammatory reaction when placed in muscle, and moderate inflammation when implanted into bone. The resorption time was more than 1 year. Bone healing at sites of implantation was slower than at control sites.

Osteotomy site healing following mandibular sagittal split osteotomy and rigid fixation with polylactide biodegradable screws

Follow-up of 47 patients, treated using mandibular bilateral sagittal split osteotomy and self-reinforced poly-L-lactide acid (SR-PLLA) screws for rigid internal fixation, is presented. The focus was on clinical and radiological osteotomy healing. The average follow-up time was 2.1 years (range 0.5-5 years). Clinical recovery and radiological osteotomy healing during follow-up were uneventful. Osteolytic changes were seen around the SR-PLLA screws in 27% of cases. The majority of the screw canals remained as radiolucent shadows without bony filling.

Generation of a new protein purification matrix by loading ceramic hydroxyapatite with metal ions--demonstration with poly-histidine tagged green fluorescent protein

The gene encoding the green fluorescent protein (GFP) from the jellyfish Aequorea victoria, was inserted under transcriptional control of the polyhedrin promoter of the Autographa californica nuclear polyhedrosis virus and expressed in the Spodoptera frugiperda insect cell line Sf9 during viral infection. The baculovirus transfervector pBlueBacHisB was used for constructing the recombinant baculovirus, so that the green fluorescent protein could be tagged with a poly-histidine tail. This fusion protein was utilized as a marker for evaluating the properties of metal ion loaded ceramic hydroxyapatite as a matrix in protein purification. Ceramic hydroxyapatite loaded with Zn(II) was the best choice for purifying this poly-histidine tagged GFP, followed by Fe(III) of the metal ions tested. Ni(II) that is superior especially in many poly-histidine purification systems did not, when loaded to hydroxyapatite, have binding properties comparable to Zn(II) or Fe(III). Elution of poly-histidine tagged GFP was best performed with phosphate buffers or EDTA that could compete with the phosphate molecules in hydroxyapatite or complexly bind the metal ions, respectively.

The lamprey (Lampetra fluviatilis) erythrocyte; morphology, ultrastructure, major plasma membrane proteins and phospholipids, and cytoskeletal organization

The aim of this study was to characterize the erythrocyte of the lamprey (Lampetra fluviatilis), a primitive vertebrate. The lamprey erythrocyte predominantly has a non-axisymmetric stomatocytelike shape. It has a nucleus and a haemoglobin-filled cytosol with a few organelles and vesicular structures. Surprisingly, there is no marginal band of microtubules. Sodium dodecylsulphate polyacrylamide gel electrophoresis followed by Coomassie blue staining of isolated plasma membranes revealed a single band at the level of the human spectrin doublet. Major bands also occurred at approximately 175 kDa and comigrating with human erythrocyte actin (approximately 45 kDa). The presence of spectrin, actin and vimentin was shown by immunoblotting. Band 3 protein, the anion exchanger in higher vertebrates, seemed to be highly deficient or lacking, as was also the case with ankyrin. Confocal laser scanning microscopy combined with immunocytochemical methods showed spectrin, actin and vimentin mainly to be localized around the nucleus, from where actin- and vimentin-strands extended out into the cytoplasm. Actin also seemed to be present at the plasma membrane. Phospholipid analyses of plasma membrane preparations showed the presence of the same four major phospholipid groups as in the human erythrocyte, although with higher and lower amounts of phosphatidylcholine and sphingomyelin, respectively. The low fluorescein isothiocyanate conjugated annexin V binding, as monitored by flow cytometry, indicated that phosphatidylserine is mainly confined to the inner membrane leaflet in the lamprey erythrocyte plasma membrane.

Fixation of mandibular body osteotomies using biodegradable amorphous self-reinforced (70L:30DL) polylactide or metal lag screws: an experimental study in sheep

Mandibular body osteotomies were fixed in nine sheep using new totally amorphous (70L:30DL), self-reinforced, polylactide (SR-PLA) lag screws and in nine sheep using standard stainless steel lag screws. No intermaxillary fixation was used. During follow-up, radiological, histological and microradiological studies were undertaken at 3, 6, 12 and 24 weeks. In both groups, all osteotomies consolidated at similar rates and no adverse reaction to the screws was seen. However, displacements of the fixed osteotomy fragments were common in both groups during the first 3 weeks. The biocompatibility of SR-PLA during the follow-up period was found to be good. Only initial signs of biodegradation were seen. The results of this study indicate that (70L:30DL) SR-PLA has potential for use as a fixation screw material in oral and maxillofacial surgery, and that further studies using this material are justified.

Mixture of epsilon-caprolactone-lactide copolymer and tricalcium phosphate: a histological and immunohistochemical study of tissue reactions

In cranio-maxillofacial surgery, bone transplantation is needed for treatment of bony defects. An autograft, allograft or biomaterial can be used. Autogenous bone grafts are considered to be the best materials available, but there are some disadvantages in their use including donorsite morbidity, need for a second operative site and limited graft supply. A search for new bone-graft materials therefore remains necessary. We prepared a mixture of tricalcium phosphate (TCP), which is a resorbable, non-toxic, osteoconductive ceramic material and epsilon-caprolactone-lactide copolymer P(epsilon-CL/DL-LA), a resorbable polymer, and placed it in the dermis and in mandibular bone defects in 13 rabbits. Follow-up times were two, three, seven, eight, 12, 15 and 18 weeks, tissue reactions were assessed, histologically and immunohistochemically. Times of resorption of the material from tissues were reported. We found that the mixture caused a mild inflammatory reaction when placed in bone and severe inflammation when placed in dermis. No highly fluorescent layer of tenascin or fibronectin was found surrounding the implant area. The mixture was excellent to handle and very easy to place into bone defects. The results are promising and have led us to continue development of the mixture.

Lag-screw fixation of anterior mandibular fractures using biodegradable polylactide screws: a preliminary report

PURPOSE

The purpose of this study was to evaluate the utility of biodegradable, self-reinforced poly-L-lactide screws (SR-PLLA) for lag-screw fixation of anterior mandibular fractures.

PATIENTS AND METHODS

SR-PLLA lag-screws were used to stabilize anterior mandibular fractures in 11 patients. Maxillomandibular fixation was used to treat concomitant mandibular condyle fractures for 2 weeks in four patients and for 1 and 5 weeks in two patients. Clinical and radiologic follow-up lasted for 6 months in 36% of patients and for 1 year in 64%.

RESULTS

Healing of all anterior fractures was uneventful, with no displacement or delay of bony union. No adverse reactions to the biodegradable screws were seen during follow-up.

CONCLUSION

Biodegradable SR-PLLA screw fixation seems to be a new and promising way of treating anterior mandibular fractures.

A microplate-based fluorometric assay for monitoring human cancer cell attachment to cortical bone

A microplate-based fluorometric assay was developed for quantitation of cancer cell attachment to bone matrix. To evaluate this model system we used a panel of human cancer cell lines, including the human breast cancer cell line MDA-MB-231. For the assay, bovine cortical bone from the shaft of the femur was cut, turned, and sliced to 6-mm-diameter round 200-microm-thin disks and placed into the wells of a 96-well microplate. A fluorescent dye 2', 7'-bis(2-carboxyethyl-5(6)-carboxyfluorescein (BCECF-AM) and a microplate fluorometer equipped with a standard filter set for fluorescein isothiocyanate were used to detect the cells attached to the bone disks. The fluorescence was enhanced during the measurement step by using a K+ solution (pH 8.0) containing the H+/K+ ionophore nigericin, which equilibrates internal and external pH. By taking advantage of the pH sensitivity of BCECF, the fluorescence intensity in the assay was increased 2.5 times compared to cells loaded with calcein. The specificity of the assay was demonstrated with a specific immuneserum raised against the MDA-MB-231 cell line. The assay can be completed in 1 h and permits the use of a large number of samples and is therefore useful for screening potential drug candidates that could block cancer cell attachment to bone material. Moreover, the assay described can easily be used to characterize molecular structures involved in cell attachment to bone.

Radiologic changes of the temporomandibular joint after condylar fractures in childhood

OBJECTIVE

The purpose of this investigation was to study the radiologic outcomes of pediatric condylar fractures.

STUDY DESIGN

Radiographs of 37 patients with 45 condylar fractures that had been diagnosed at the Department of Oral and Maxillofacial Surgery, Helsinki University Central Hospital were retrospectively reviewed. The frequency and characteristics of incomplete remodeling at an average of 4.1 years after the injury were studied. The influence of age and fracture type on remodeling were considered.

RESULTS

Incomplete remodeling was observed after 56% of the fractures. The most frequent signs of incomplete remodeling were alteration in the configuration of the surface of the condylar head and deformation of the condylar neck. Incomplete remodeling was frequently (83%) related to fracture dislocation. For this fracture type the radiologic prognosis seems poor in all age groups. A difference in ramus height between the 2 sides was observed in 52% of the fractures, particularly frequently (80%) after fracture dislocation.

CONCLUSIONS

Radiologic aberrations are frequent after pediatric condylar fractures. Dislocated fractures, in particular, need special attention and long-lasting clinical follow-up.

Fibrous wound repair associated with biodegradable poly-L/D-lactide copolymer implants: study of the expression of tenascin and cellular fibronectin

Extracellular matrix (ECM) proteins are known to play a role in inflammatory and hyperplastic processes. Our aim in the present study was to study the distribution of tenascin (Tn), cellular fibronectins (cFn) and myofibroblasts around biodegradable poly-L/D-lactide (PLA) implants with monoclonal antibodies (MAb). Ethylene-oxide and gamma-irradiation sterilized PLA plate-type implants were inserted into the dorsal subcutaneous tissue of ten adult rabbits. Follow-up times were 4, 12, 16, 36 and 48 wk. Only some inflammatory cells were observed. In electron microscopy, a close coherence between the implant and the stromal tissue was seen. Immunoreactivity for Tn, cFn and alpha-actin was detected as a distinct layer bordering the implant, regardless of the sterilization method for the first 36 wk. From week 36 onwards, Tn immunoreactivity was downregulated while cFn immunoreactivity still persisted. A moderate upregulation for myofibroblasts was seen on the week 48 specimens, when hydrolysation of PLA implant had started. The persistent content of myofibroblasts, Tn and cFn suggests a prolonged wound healing produced by PLA implants. The absence of Tn at the week 48 specimens suggests that cFn, rather than Tn may be needed for alpha-actin-mediated contraction by myofibroblasts.