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Riitta Suuronen

Publications and source records attributed to Riitta Suuronen.

18 recordsLinked to original sources
PubMed2006

Tyrosine-derived polycarbonate membrane in treating mandibular bone defects. An experimental study.

This study was designed to evaluate the suitability of a novel bioabsorbable material in treating bone defects. A poly(desaminotyrosyl-tyrosine-ethyl ester carbonate) (PDTE carbonate) membrane (thickness 0.2-0.3 mm) was implanted into the mandibular angle of 20 New Zealand White rabbits to cover a through-and-through defect (12 x 6 mm). In group 1, the defects were left unfilled but covered with membrane and in group 2 the defects were filled with bioactive glass mesh and covered with membrane, too. Controls were left uncovered and unfilled. The animals were followed for 6, 12, 24 and 52 weeks, respectively. The material was evaluated by qualitative analysis of histological reactions and newly formed bone. We found that PDTE carbonate elicited a modest foreign body reaction in the tissues, which was uniform throughout the study. New bone formation was seen in all samples after six weeks. Group 1 had more new bone formation until 24 weeks and after this the difference settled. Based on findings of this study it was concluded that PDTE carbonate membranes have good biocompatibility and are sufficient to enhance bone growth without additional supportive matrix.

Animals↗
PubMed2006

Reconstruction of internal orbital wall fracture with iliac crest free bone graft: clinical, computed tomography, and magnetic resonance imaging follow-up study.

BACKGROUND: The purpose of this study was to clinically and radiologically assess the outcome of internal orbital reconstruction with an iliac bone graft. METHODS: Twenty-four consecutive patients with unilateral orbital wall fractures were enrolled in this prospective study. A medial cortical wall from the anterior ilium was used for reconstruction. At each follow-up visit, globe posture, diplopia, and eye movements were assessed. Coronal and sagittal computed tomography and magnetic resonance imaging were used to observe graft posture, bone defects, and intraorbital soft-tissue changes. RESULTS: Most fractures (46 percent) were pure orbital floor fractures. The mean follow-up was 7.8 months. One patient with medial wall and floor fractures required reoperation because of insufficient bone graft. At the last follow-up, this was the only patient (4 percent) with both enophthalmos (2 mm) and hypophthalmos (3 mm). Five patients (21 percent) had hypophthalmos (> 1 mm) at the end of the study. Resorption and remodeling were detected in all grafts, but no grafts were totally resorbed. Sagittal or coronal bone graft postures were assessed as good in 18 orbits (75 percent). Bone defects (> 10 mm) at reconstructed areas were detected in 13 orbits (54 percent). Scar tissue was observed only in three reconstructed orbits (13 percent). Diplopia in central field of vision was registered in seven patients preoperatively but in none at the end of the study. CONCLUSIONS: The resorption rate was high, but most of it was advantageous remodeling. Overall outcome was good. Secondary operations led to poor outcomes. Thin computed tomography and magnetic resonance imaging sections (< or = 2 mm) are needed to evaluate accurately bone graft placement and posture and orbital volume.

Adult↗
PubMed2005

Failed dental implants - clinical, radiological and bacteriological findings in 17 patients.

AIM: The aim of this study was to evaluate the reasons for implant failure in two Oral and Maxillofacial Units in Helsinki. Seventeen patients, who lost 30 implants were included in this study. MATERIAL AND METHODS: The patients and implants were studied clinically, radiologically and microbiologically. RESULTS: Most patients did not have any symptom indicating failure; hence, the failures were noticed mainly by the clinicians when instability of the fixture or of the prosthetic reconstruction became obvious. Radiolucency around the fixture was the most frequent radiological finding. Twenty per cent of the fixtures were located in insufficient bone. Ninety seven per cent of the bacterial cultures were positive, Streptococcus milleri being the most commonly identified aerobic and Fusobacterium nucleatum the most commonly anaerobic bacteria. CONCLUSION: The most critical time for success is immediately after prosthetic loading. Hence, implants should be placed in the optimal position to facilitate prosthetic reconstruction and loading.

Adult↗
PubMed2005

Assessment of material- and technique-related complications following sagittal split osteotomies stabilized by biodegradable polylactide screws.

OBJECTIVE: The aim of this retrospective clinical study was to determine whether there are any material-related problems and increased occurrence of postoperative mandibular nerve and temporomandibular joint dysfunctions in connection with the use of biodegradable self-reinforced poly-L-lactide (SR-PLLA) screws for bone fixation after bilateral sagittal split osteotomies (BSSO). STUDY DESIGN: Forty consecutive patients who underwent BSSO and mandibular advancement that included fragment fixation using SR-PLLA screws were monitored for an average of 2.2 years postoperatively. RESULTS: The osteotomy sites healed uneventfully with no adverse reactions. The incidence of postoperative sensory disturbances of the inferior alveolar nerve was 27%. Symptoms of temporomandibular joint disorders (TMJD) observed preoperatively in 73% of patients were reduced to 48% after surgery. CONCLUSION: The occurrence of postoperative sensory disturbances and TMJD symptoms in this study did not deviate strikingly from that of other studies using conventional osteosynthesis. No specific complications related to the screw material were observed.

Absorbable Implants↗
PubMed2005

Oral and salivary parameters in patients with rheumatic diseases.

We studied the presence of secondary Sjögren's syndrome (SS) and the composition of saliva, prevalence of oral pathogens, periodontitis, mouth mucosa, and teeth in patients with various rheumatic diseases and in healthy controls. The hypothesis was that different rheumatic diseases might cause differences in oral health characteristics because of the liability of secondary SS in the patients. The study involved 77 patients and 77 age-matched and sex-matched controls. Twenty patients were suffering from spondylarthropathy (SPA), 18 from ankylosing spondylitis (AS), 24 from rheumatoid arthritis (RA), and 15 from mixed connective tissue disease (MCTD). Clinical and radiographic oral health status was recorded and salivary flow rates were measured. Selected salivary proteins and immunoglobulins were analysed by routine methods. Minor salivary gland biopsy samples were taken from the patients for assessment of inflammatory focus scores. Differences between patients and controls and in between the different rheumatic diseases were analysed statistically. Secondary SS was diagnosed in 39% (30/77) of the patients. A severe periodontal condition (community periodontal index of treatment needs score 3 or 4) occurred in 58% (45/77) of the rheumatic patients compared with only 26% (20/77) of the controls (p < 0.0001). The severity of focal sialadenitis (focus score) correlated significant with salivary IgA, IgG, and IgM concentrations. Salivary albumin, total protein, IgG, and IgM concentrations were higher in all patient groups than in the controls. The number of patients with low salivary flow rates was higher in all patient groups compared to controls. Oral yeast counts were significantly higher in the patients than in the controls (p < 0.001). In a subgroup analysis, patients with SS had higher values for salivary IgA and IgM than patients without SS. Dental caries and oral lactobacilli were more frequent in patients with SS, but SS was not associated with periodontitis. No major differences were noted in other salivary biochemical parameters between these two groups. Patients with rheumatic diseases, irrespective of specific diagnosis, thus had various alterations in salivary flow and composition and oral health. The findings may reflect the autoimmune inflammation of the salivary glands frequently observed in these patients.

Adult↗
PubMed2005

Have the causes of maxillofacial fractures changed over the last 16 years in Finland? An epidemiological study of 725 fractures.

A retrospective study was undertaken to assess causes of maxillofacial fractures in Helsinki in 1981 and 1997. Hospital records of 725 patients were analyzed according to several factors including age, sex, cause of fracture and time of the injury. The time intervals between the accident and hospital examination were also evaluated. Number of maxillofacial fractures was 318 in 1981 and 407 in 1997 (27.9% increase) and most patients were men. The male to female ratio was 2.8:1 in 1981, 3:1 in 1997. In 1981, most affected patients were in the age group of 31-40 years (33.2% of men, 28.9% of women). Sixteen years later the most affected age group was 41-50 years (23.3% of men, 30.4% of women). Assault was the cause of the injury in 42% of patients followed by traffic accidents (26%) and fall (17%). During the study period violence had become more severe in nature. Kicking as the cause of maxillofacial fracture increased by 7.3% and use of a weapon by 5.7% between the years studied. Bicycle accidents increased by 19.3% but motor vehicle accidents decreased by 31.6% between the years. Falls, and bicycle and pedestrian accidents were the causes that accounted for most of the increase in maxillofacial fracture. In 1997, maxillofacial fractures were slightly more common from June to August and from Friday to Sunday than at other times (45.2 and 50%, respectively).

Accidents, Traffic↗
PubMed2004

Bioabsorbable fixation devices in trauma and bone surgery: current clinical standing.

Bioabsorbable fixation devices are increasingly used in trauma, orthopedic and craniomaxillofacial surgery. The devices are essentially made of polylactic acid and/or polyglycolic acid polymers. Ultra-high-strength implants are manufactured from such polymers using self-reinforcing techniques. Implants are available for stabilization of fractures, osteotomies, bone grafts and fusions, as well as for reattachment of ligaments, tendons, meniscal tears and other soft tissue structures. As these implants are completely absorbed, the need for a removal operation is overcome and long-term interference with tendons, nerves and the growing skeleton is avoided. The risk of implant-associated stress shielding, peri-implant osteoporosis and infections is reduced. Implants do not interfere with clinical imaging. Current clinical use of bioabsorbable devices is reviewed.

Absorbable Implants↗
PubMed2004

Bioabsorbable self-reinforced plates and screws in craniomaxillofacial surgery.

Bioabsorbable fixation devices have been used in craniomaxillofacial (CMF) surgery since the early 70's. In our departments the experimental use started in the 80's with self-reinforced (SR) polylactide devices. The first clinical operations were carried out in 1991. Since that time, we have used different types of self-reinforced bioabsorbable devices in the fixation of several hundreds of osteotomies and fractures. Patients' acceptance has been generally excellent and very few complications occurred during this follow-up of over 10 years. The complications have been minor and have not affected the end results of the operations. In only one oncologic patient, the devices needed to be removed and replaced with a rigid reconstruction plate. The minor complications consisted mainly of a few infections, dehiscence of the wound and plate exposure together with granulation tissue in the operation field. No implant-specific complications were recorded. However, there is a learning curve for the surgeon, as there is with all new methods introduced. Based on our experience, self-reinforced bioabsorbable devices are safe to be used in several indications in the craniomaxillofacial skeleton, also in load-shearing situations.

Absorbable Implants↗
PubMed2003

Prevalence and physical status of human papillomavirus in squamous cell carcinomas of the head and neck.

Fresh-frozen biopsies were obtained from 61 patients at diagnosis of squamous cell carcinoma of the head and neck (HNSCC) for study of the prevalence and physical status of human papillomavirus (HPV) DNA. The frequency of HPV DNA and genotypes were determined by SPF10 PCR screening with a general probe hybridization and INNO-LiPA HPV genotyping assay. In addition, a single-phase PCR with primers FAP 59/64 and a nested PCR with primers CP 65/70 and CP 66/69 served to detect particularly cutaneous HPV types. By the sensitive SPF10 PCR and INNO-LiPA assay, 37 of 61 (61%) samples were positive for HPV. HPV-16 was the most frequently detected type (31 of 37, 84%). Multiple infections were found in 8 of 37 (22%) of the HPV-positive samples, and co-infection by HPV-16 and HPV-33 was predominant. No cutaneous HPV types were detected. Patients with HPV-positive tumors had similar prognosis as those with HPV-negative ones. Real-time PCR analysis of the HPV-16 positive samples indicated the presence of integrated (11 of 23, 48%), episomal (8 of 23, 35%) and mixed forms (4 of 23, 17%) of HPV DNA. The viral load of HPV DNA exhibited large variation. The median copy numbers of E6 DNA in tonsillar specimens were approximately 80,000 times higher than that in nontonsillar HNSCC ones. Patients with episomal viral DNA were more frequently found to have large (T3-T4) tumors at diagnosis than were those with integrated or mixed forms.

Adult↗
PubMed2003

Tissue reactions of subcutaneously implanted mixture of epsilon-caprolactone-lactide copolymer and tricalcium phosphate. An electron microscopic evaluation in sheep.

Biodegradable polymers, mainly derivates of alpha-hydroxy acids, are widely used today in oral- and maxillofacial surgery, orthopedics, and other fields of surgery. These biomaterials are well tolerated by living tissue and fracture fixation devices made of polylactic or polyglycolic acid are clinically widely used today. Still, there are some problems in application of biodegradable polymers. Abacterial inflammatory reactions have been noticed after the clinical introduction of these devices. Both swelling and pain at the site of implantation have also been reported. The etiology of this inflammatory reaction is still unknown, despite the numerous studies. Therefore, the aim of the present study was to further characterize this inflammatory reaction in detail, by electronmicroscopy. We prepared a mixture of epsilon-caprolactone-lactide copolymer and tricalcium phosphate and placed it in the dermis in 12 sheep. Follow-up times were 9, 14, 24, and 52 weeks. We found that the mixture caused a mild inflammatory reaction. There were no signs of cell damage. Fibroblasts, macrophages, and eosinophils were found adjacent to the copolymer. The mixture is easy to handle and can be moulded into different shapes in room temperature. The results encourage us to continue our studies to develop a filling material for bone defects.

Journal Article↗
PubMed2003

Spotlight on naturally absorbable osteofixation devices.

The practice of using implants is growing day by day, and more foreign materials are being inserted for various indications. The field of implantology thus deserves intensive research and careful evaluation of results. Solutions to overcome current problems and risks are necessary. It has taken a long time to arrive at where we are now. Bioabsorbable devices were explored in the 1960s for surgical bone fixation. Failures were followed by changes in ways of thinking and innovations. Improvements in the strength properties and biocompatibility were achieved. Bioabsorbable polymeric materials such as high-molecular-weight polymers were used and also reinforced with other material or, more recently, by self-reinforcement to produce small yet strong devices. New generations of implants include those that contain bioactive substances such as antibiotics and growth factors. Developments in bioabsorbable materials continue to accommodate the new way of thinking brought about by the emergence of the field of tissue engineering. Surgeons, conversely, are also inventing new surgical techniques and methods to exploit the plastic and bioabsorbability properties of these materials for the better future of our patients. Such a multidisciplinary approach that involves surgeons and materials scientists should help to find solutions to the current limitations of these devices.

Absorbable Implants↗
PubMed2002

The use of bioabsorbable osteofixation devices in craniomaxillofacial surgery.

Because of problems associated with the conventional osteofixation devices used in craniomaxillofacial surgery, bioabsorbable devices have presented an appealing alternative. Devices made of the polymers polyglycolide (PGA) and polylactide (PLA) and their copolymers (PLGA and PLDLA) are currently the most commonly used. Strong implants can be manufactured from these polymers with a self-reinforcing technique and used in the treatment of fractures and osteotomies. Self-reinforced devices have been studied for nearly 2 decades by our multidisciplinary research group for internal fixation of the bone in both experimental and clinical settings. In craniomaxillofacial fractures and osteotomies they have been used for as long as 10 years with no significant clinical problems. Because of more favored degradation characteristics, currently the copolymer devices (PLDLA and PLGA) represent the advancing front in the application of absorbable devices in craniomaxillofacial surgery. By using bioabsorbable devices, several problems associated with conventional biostable devices can be avoided, especially in children. New techniques that are not possible with biostable devices can be developed by using bioabsorbable devices, too. Our experience with and research on self-reinforced devices are shared here.

Absorbable Implants↗